After a decade or extra the place Single-Web page-Functions generated by
JavaScript frameworks have
develop into the norm, we see that server-side rendered HTML is changing into
standard once more, additionally due to libraries reminiscent of HTMX or Turbo. Writing a wealthy net UI in a
historically server-side language like Go or Java is not simply doable,
however a really enticing proposition.
We then face the issue of find out how to write automated assessments for the HTML
components of our net functions. Whereas the JavaScript world has advanced highly effective and refined methods to check the UI,
ranging in dimension from unit-level to integration to end-to-end, in different
languages we would not have such a richness of instruments obtainable.
When writing an online utility in Go or Java, HTML is often generated
by templates, which comprise small fragments of logic. It’s actually
doable to check them not directly by end-to-end assessments, however these assessments
are sluggish and costly.
We are able to as an alternative write unit assessments that use CSS selectors to probe the
presence and proper content material of particular HTML parts inside a doc.
Parameterizing these assessments makes it straightforward so as to add new assessments and to obviously
point out what particulars every take a look at is verifying. This method works with any
language that has entry to an HTML parsing library that helps CSS
selectors; examples are offered in Go and Java.
Degree 1: checking for sound HTML
The primary factor we need to examine is that the HTML we produce is
mainly sound. I do not imply to examine that HTML is legitimate in response to the
W3C; it will be cool to do it, nevertheless it’s higher to begin with a lot less complicated and sooner checks.
As an example, we would like our assessments to
break if the template generates one thing like
<div>foo</p>
Let’s examine find out how to do it in levels: we begin with the next take a look at that
tries to compile the template. In Go we use the usual html/template
bundle.
Go
func Test_wellFormedHtml(t *testing.T) { templ := template.Should(template.ParseFiles("index.tmpl")) _ = templ }
In Java, we use jmustache
as a result of it is quite simple to make use of; Freemarker or
Velocity are different frequent selections.
Java
@Check void indexIsSoundHtml() { var template = Mustache.compiler().compile( new InputStreamReader( getClass().getResourceAsStream("/index.tmpl"))); }
If we run this take a look at, it can fail, as a result of the index.tmpl
file does
not exist. So we create it, with the above damaged HTML. Now the take a look at ought to go.
Then we create a mannequin for the template to make use of. The applying manages a todo-list, and
we will create a minimal mannequin for demonstration functions.
Go
func Test_wellFormedHtml(t *testing.T) {
templ := template.Should(template.ParseFiles("index.tmpl"))
mannequin := todo.NewList()
_ = templ
_ = mannequin
}
Java
@Check
void indexIsSoundHtml() {
var template = Mustache.compiler().compile(
new InputStreamReader(
getClass().getResourceAsStream("/index.tmpl")));
var mannequin = new TodoList();
}
Now we render the template, saving the leads to a bytes buffer (Go) or as a String
(Java).
Go
func Test_wellFormedHtml(t *testing.T) {
templ := template.Should(template.ParseFiles("index.tmpl"))
mannequin := todo.NewList()
var buf bytes.Buffer
err := templ.Execute(&buf, mannequin)
if err != nil {
panic(err)
}
}
Java
@Check
void indexIsSoundHtml() {
var template = Mustache.compiler().compile(
new InputStreamReader(
getClass().getResourceAsStream("/index.tmpl")));
var mannequin = new TodoList();
var html = template.execute(mannequin);
}
At this level, we need to parse the HTML and we anticipate to see an
error, as a result of in our damaged HTML there’s a div
aspect that
is closed by a p
aspect. There’s an HTML parser within the Go
commonplace library, however it’s too lenient: if we run it on our damaged HTML, we do not get an
error. Fortunately, the Go commonplace library additionally has an XML parser that may be
configured to parse HTML (due to this Stack Overflow reply)
Go
func Test_wellFormedHtml(t *testing.T) {
templ := template.Should(template.ParseFiles("index.tmpl"))
mannequin := todo.NewList()
// render the template right into a buffer
var buf bytes.Buffer
err := templ.Execute(&buf, mannequin)
if err != nil {
panic(err)
}
// examine that the template might be parsed as (lenient) XML
decoder := xml.NewDecoder(bytes.NewReader(buf.Bytes()))
decoder.Strict = false
decoder.AutoClose = xml.HTMLAutoClose
decoder.Entity = xml.HTMLEntity
for {
_, err := decoder.Token()
swap err {
case io.EOF:
return // We're accomplished, it is legitimate!
case nil:
// do nothing
default:
t.Fatalf("Error parsing html: %s", err)
}
}
}
This code configures the HTML parser to have the precise degree of leniency
for HTML, after which parses the HTML token by token. Certainly, we see the error
message we wished:
--- FAIL: Test_wellFormedHtml (0.00s) index_template_test.go:61: Error parsing html: XML syntax error on line 4: sudden finish aspect </p>
In Java, a flexible library to make use of is jsoup:
Java
@Check
void indexIsSoundHtml() {
var template = Mustache.compiler().compile(
new InputStreamReader(
getClass().getResourceAsStream("/index.tmpl")));
var mannequin = new TodoList();
var html = template.execute(mannequin);
var parser = Parser.htmlParser().setTrackErrors(10);
Jsoup.parse(html, "", parser);
assertThat(parser.getErrors()).isEmpty();
}
And we see it fail:
java.lang.AssertionError: Anticipating empty however was:<[<1:13>: Unexpected EndTag token [</p>] when in state [InBody],
Success! Now if we copy over the contents of the TodoMVC
template to our index.tmpl
file, the take a look at passes.
The take a look at, nonetheless, is just too verbose: we extract two helper capabilities, in
order to make the intention of the take a look at clearer, and we get
Go
func Test_wellFormedHtml(t *testing.T) { mannequin := todo.NewList() buf := renderTemplate("index.tmpl", mannequin) assertWellFormedHtml(t, buf) }
Java
@Check void indexIsSoundHtml() { var mannequin = new TodoList(); var html = renderTemplate("/index.tmpl", mannequin); assertSoundHtml(html); }
Degree 2: testing HTML construction
What else ought to we take a look at?
We all know that the seems to be of a web page can solely be examined, in the end, by a
human taking a look at how it’s rendered in a browser. Nonetheless, there’s typically
logic in templates, and we would like to have the ability to take a look at that logic.
One could be tempted to check the rendered HTML with string equality,
however this system fails in observe, as a result of templates comprise loads of
particulars that make string equality assertions impractical. The assertions
develop into very verbose, and when studying the assertion, it turns into troublesome
to know what it’s that we’re attempting to show.
What we want
is a method to say that some components of the rendered HTML
correspond to what we anticipate, and to ignore all the small print we do not
care about. A method to do that is by working queries with the CSS selector language:
it’s a highly effective language that enables us to pick out the
parts that we care about from the entire HTML doc. As soon as we’ve
chosen these parts, we (1) depend that the variety of aspect returned
is what we anticipate, and (2) that they comprise the textual content or different content material
that we anticipate.
The UI that we’re purported to generate seems to be like this:
There are a number of particulars which can be rendered dynamically:
- The variety of objects and their textual content content material change, clearly
- The type of the todo-item adjustments when it is accomplished (e.g., the
second) - The “2 objects left” textual content will change with the variety of non-completed
objects - One of many three buttons “All”, “Lively”, “Accomplished” will likely be
highlighted, relying on the present url; as an example if we resolve that the
url that reveals solely the “Lively” objects is/energetic
, then when the present url
is/energetic
, the “Lively” button must be surrounded by a skinny purple
rectangle - The “Clear accomplished” button ought to solely be seen if any merchandise is
accomplished
Every of this considerations might be examined with the assistance of CSS selectors.
It is a snippet from the TodoMVC template (barely simplified). I
haven’t but added the dynamic bits, so what we see right here is static
content material, offered for instance:
index.tmpl
<part class="todoapp"> <ul class="todo-list"> <!-- These are right here simply to indicate the construction of the record objects --> <!-- Listing objects ought to get the category `accomplished` when marked as accomplished --> <li class="accomplished"> ② <div class="view"> <enter class="toggle" sort="checkbox" checked> <label>Style JavaScript</label> ① <button class="destroy"></button> </div> </li> <li> <div class="view"> <enter class="toggle" sort="checkbox"> <label>Purchase a unicorn</label> ① <button class="destroy"></button> </div> </li> </ul> <footer class="footer"> <!-- This must be `0 objects left` by default --> <span class="todo-count"><sturdy>0</sturdy> merchandise left</span> ⓷ <ul class="filters"> <li> <a class="chosen" href="#/">All</a> ④ </li> <li> <a href="#/energetic">Lively</a> </li> <li> <a href="#/accomplished">Accomplished</a> </li> </ul> <!-- Hidden if no accomplished objects are left ↓ --> <button class="clear-completed">Clear accomplished</button> ⑤ </footer> </part>
By trying on the static model of the template, we will deduce which
CSS selectors can be utilized to establish the related parts for the 5 dynamic
options listed above:
characteristic | CSS selector | |
---|---|---|
① | All of the objects | ul.todo-list li |
② | Accomplished objects | ul.todo-list li.accomplished |
⓷ | Gadgets left | span.todo-count |
④ | Highlighted navigation hyperlink | ul.filters a.chosen |
⑤ | Clear accomplished button | button.clear-completed |
We are able to use these selectors to focus our assessments on simply the issues we need to take a look at.
Testing HTML content material
The primary take a look at will search for all of the objects, and show that the information
arrange by the take a look at is rendered appropriately.
func Test_todoItemsAreShown(t *testing.T) { mannequin := todo.NewList() mannequin.Add("Foo") mannequin.Add("Bar") buf := renderTemplate(mannequin) // assert there are two <li> parts contained in the <ul class="todo-list"> // assert the primary <li> textual content is "Foo" // assert the second <li> textual content is "Bar" }
We’d like a approach to question the HTML doc with our CSS selector; an excellent
library for Go is goquery, that implements an API impressed by jQuery.
In Java, we preserve utilizing the identical library we used to check for sound HTML, specifically
jsoup. Our take a look at turns into:
Go
func Test_todoItemsAreShown(t *testing.T) { mannequin := todo.NewList() mannequin.Add("Foo") mannequin.Add("Bar") buf := renderTemplate("index.tmpl", mannequin) // parse the HTML with goquery doc, err := goquery.NewDocumentFromReader(bytes.NewReader(buf.Bytes())) if err != nil { // if parsing fails, we cease the take a look at right here with t.FatalF t.Fatalf("Error rendering template %s", err) } // assert there are two <li> parts contained in the <ul class="todo-list"> choice := doc.Discover("ul.todo-list li") assert.Equal(t, 2, choice.Size()) // assert the primary <li> textual content is "Foo" assert.Equal(t, "Foo", textual content(choice.Nodes[0])) // assert the second <li> textual content is "Bar" assert.Equal(t, "Bar", textual content(choice.Nodes[1])) } func textual content(node *html.Node) string { // Somewhat mess on account of the truth that goquery has // a .Textual content() technique on Choice however not on html.Node sel := goquery.Choice{Nodes: []*html.Node{node}} return strings.TrimSpace(sel.Textual content()) }
Java
@Check void todoItemsAreShown() throws IOException { var mannequin = new TodoList(); mannequin.add("Foo"); mannequin.add("Bar"); var html = renderTemplate("/index.tmpl", mannequin); // parse the HTML with jsoup Doc doc = Jsoup.parse(html, ""); // assert there are two <li> parts contained in the <ul class="todo-list"> var choice = doc.choose("ul.todo-list li"); assertThat(choice).hasSize(2); // assert the primary <li> textual content is "Foo" assertThat(choice.get(0).textual content()).isEqualTo("Foo"); // assert the second <li> textual content is "Bar" assertThat(choice.get(1).textual content()).isEqualTo("Bar"); }
If we nonetheless have not modified the template to populate the record from the
mannequin, this take a look at will fail, as a result of the static template
todo objects have totally different textual content:
Go
--- FAIL: Test_todoItemsAreShown (0.00s) index_template_test.go:44: First record merchandise: need Foo, acquired Style JavaScript index_template_test.go:49: Second record merchandise: need Bar, acquired Purchase a unicorn
Java
IndexTemplateTest > todoItemsAreShown() FAILED org.opentest4j.AssertionFailedError: Anticipating: <"Style JavaScript"> to be equal to: <"Foo"> however was not.
We repair it by making the template use the mannequin knowledge:
Go
<ul class="todo-list"> {{ vary .Gadgets }} <li> <div class="view"> <enter class="toggle" sort="checkbox"> <label>{{ .Title }}</label> <button class="destroy"></button> </div> </li> {{ finish }} </ul>
Java – jmustache
<ul class="todo-list"> {{ #allItems }} <li> <div class="view"> <enter class="toggle" sort="checkbox"> <label>{{ title }}</label> <button class="destroy"></button> </div> </li> {{ /allItems }} </ul>
Check each content material and soundness on the identical time
Our take a look at works, however it’s a bit verbose, particularly the Go model. If we’ll have extra
assessments, they are going to develop into repetitive and troublesome to learn, so we make it extra concise by extracting a helper operate for parsing the html. We additionally take away the
feedback, because the code must be clear sufficient
Go
func Test_todoItemsAreShown(t *testing.T) { mannequin := todo.NewList() mannequin.Add("Foo") mannequin.Add("Bar") buf := renderTemplate("index.tmpl", mannequin) doc := parseHtml(t, buf) choice := doc.Discover("ul.todo-list li") assert.Equal(t, 2, choice.Size()) assert.Equal(t, "Foo", textual content(choice.Nodes[0])) assert.Equal(t, "Bar", textual content(choice.Nodes[1])) } func parseHtml(t *testing.T, buf bytes.Buffer) *goquery.Doc { doc, err := goquery.NewDocumentFromReader(bytes.NewReader(buf.Bytes())) if err != nil { // if parsing fails, we cease the take a look at right here with t.FatalF t.Fatalf("Error rendering template %s", err) } return doc }
Java
@Check void todoItemsAreShown() throws IOException { var mannequin = new TodoList(); mannequin.add("Foo"); mannequin.add("Bar"); var html = renderTemplate("/index.tmpl", mannequin); var doc = parseHtml(html); var choice = doc.choose("ul.todo-list li"); assertThat(choice).hasSize(2); assertThat(choice.get(0).textual content()).isEqualTo("Foo"); assertThat(choice.get(1).textual content()).isEqualTo("Bar"); } non-public static Doc parseHtml(String html) { return Jsoup.parse(html, ""); }
A lot better! At the very least in my view. Now that we extracted the parseHtml
helper, it is
a good suggestion to examine for sound HTML within the helper:
Go
func parseHtml(t *testing.T, buf bytes.Buffer) *goquery.Doc {
assertWellFormedHtml(t, buf)
doc, err := goquery.NewDocumentFromReader(bytes.NewReader(buf.Bytes()))
if err != nil {
// if parsing fails, we cease the take a look at right here with t.FatalF
t.Fatalf("Error rendering template %s", err)
}
return doc
}
Java
non-public static Doc parseHtml(String html) { var parser = Parser.htmlParser().setTrackErrors(10); var doc = Jsoup.parse(html, "", parser); assertThat(parser.getErrors()).isEmpty(); return doc; }
And with this, we will do away with the primary take a look at that we wrote, as we at the moment are testing for sound HTML on a regular basis.
The second take a look at
Now we’re in an excellent place for testing extra rendering logic. The
second dynamic characteristic in our record is “Listing objects ought to get the category
accomplished
when marked as accomplished”. We are able to write a take a look at for this:
Go
func Test_completedItemsGetCompletedClass(t *testing.T) { mannequin := todo.NewList() mannequin.Add("Foo") mannequin.AddCompleted("Bar") buf := renderTemplate("index.tmpl", mannequin) doc := parseHtml(t, buf) choice := doc.Discover("ul.todo-list li.accomplished") assert.Equal(t, 1, choice.Measurement()) assert.Equal(t, "Bar", textual content(choice.Nodes[0])) }
Java
@Check void completedItemsGetCompletedClass() { var mannequin = new TodoList(); mannequin.add("Foo"); mannequin.addCompleted("Bar"); var html = renderTemplate("/index.tmpl", mannequin); Doc doc = Jsoup.parse(html, ""); var choice = doc.choose("ul.todo-list li.accomplished"); assertThat(choice).hasSize(1); assertThat(choice.textual content()).isEqualTo("Bar"); }
And this take a look at might be made inexperienced by including this little bit of logic to the
template:
Go
<ul class="todo-list">
{{ vary .Gadgets }}
<li class="{{ if .IsCompleted }}accomplished{{ finish }}">
<div class="view">
<enter class="toggle" sort="checkbox">
<label>{{ .Title }}</label>
<button class="destroy"></button>
</div>
</li>
{{ finish }}
</ul>
Java – jmustache
<ul class="todo-list">
{{ #allItems }}
<li class="{{ #isCompleted }}accomplished{{ /isCompleted }}">
<div class="view">
<enter class="toggle" sort="checkbox">
<label>{{ title }}</label>
<button class="destroy"></button>
</div>
</li>
{{ /allItems }}
</ul>
So little by little, we will take a look at and add the assorted dynamic options
that our template ought to have.
Make it straightforward so as to add new assessments
The primary of the 20 suggestions from the superb speak by Russ Cox on Go
Testing is “Make it straightforward so as to add new take a look at instances“. Certainly, in Go there
is a bent to make most assessments parameterized, for this very purpose.
However, whereas Java has
good help
for parameterized assessments with JUnit 5, they are not used as a lot.
Since our present two assessments have the identical construction, we
may issue them right into a single parameterized take a look at.
A take a look at case for us will encompass:
- A reputation (in order that we will produce clear error messages when the take a look at
fails) - A mannequin (in our case a
todo.Listing
) - A CSS selector
- A listing of textual content matches that we anticipate finding once we run the CSS
selector on the rendered HTML.
So that is the information construction for our take a look at instances:
Go
var testCases = []struct { identify string mannequin *todo.Listing selector string matches []string }{ { identify: "all todo objects are proven", mannequin: todo.NewList(). Add("Foo"). Add("Bar"), selector: "ul.todo-list li", matches: []string{"Foo", "Bar"}, }, { identify: "accomplished objects get the 'accomplished' class", mannequin: todo.NewList(). Add("Foo"). AddCompleted("Bar"), selector: "ul.todo-list li.accomplished", matches: []string{"Bar"}, }, }
Java
report TestCase(String identify, TodoList mannequin, String selector, Listing<String> matches) { @Override public String toString() { return identify; } } public static TestCase[] indexTestCases() { return new TestCase[]{ new TestCase( "all todo objects are proven", new TodoList() .add("Foo") .add("Bar"), "ul.todo-list li", Listing.of("Foo", "Bar")), new TestCase( "accomplished objects get the 'accomplished' class", new TodoList() .add("Foo") .addCompleted("Bar"), "ul.todo-list li.accomplished", Listing.of("Bar")), }; }
And that is our parameterized take a look at:
Go
func Test_indexTemplate(t *testing.T) { for _, take a look at := vary testCases { t.Run(take a look at.identify, func(t *testing.T) { buf := renderTemplate("index.tmpl", take a look at.mannequin) assertWellFormedHtml(t, buf) doc := parseHtml(t, buf) choice := doc.Discover(take a look at.selector) require.Equal(t, len(take a look at.matches), len(choice.Nodes), "sudden # of matches") for i, node := vary choice.Nodes { assert.Equal(t, take a look at.matches[i], textual content(node)) } }) } }
Java
@ParameterizedTest @MethodSource("indexTestCases") void testIndexTemplate(TestCase take a look at) { var html = renderTemplate("/index.tmpl", take a look at.mannequin); var doc = parseHtml(html); var choice = doc.choose(take a look at.selector); assertThat(choice).hasSize(take a look at.matches.dimension()); for (int i = 0; i < take a look at.matches.dimension(); i++) { assertThat(choice.get(i).textual content()).isEqualTo(take a look at.matches.get(i)); } }
We are able to now run our parameterized take a look at and see it go:
Go
$ go take a look at -v === RUN Test_indexTemplate === RUN Test_indexTemplate/all_todo_items_are_shown === RUN Test_indexTemplate/completed_items_get_the_'accomplished'_class --- PASS: Test_indexTemplate (0.00s) --- PASS: Test_indexTemplate/all_todo_items_are_shown (0.00s) --- PASS: Test_indexTemplate/completed_items_get_the_'accomplished'_class (0.00s) PASS okay tdd-html-templates 0.608s
Java
$ ./gradlew take a look at > Job :take a look at IndexTemplateTest > testIndexTemplate(TestCase) > [1] all todo objects are proven PASSED IndexTemplateTest > testIndexTemplate(TestCase) > [2] accomplished objects get the 'accomplished' class PASSED
Observe how, by giving a reputation to our take a look at instances, we get very readable take a look at output, each on the terminal and within the IDE:
Having rewritten our two previous assessments in desk type, it is now tremendous straightforward so as to add
one other. That is the take a look at for the “x objects left” textual content:
Go
{ identify: "objects left", mannequin: todo.NewList(). Add("One"). Add("Two"). AddCompleted("Three"), selector: "span.todo-count", matches: []string{"2 objects left"}, },
Java
new TestCase( "objects left", new TodoList() .add("One") .add("Two") .addCompleted("Three"), "span.todo-count", Listing.of("2 objects left")),
And the corresponding change within the html template is:
Go
<span class="todo-count"><sturdy>{{len .ActiveItems}}</sturdy> objects left</span>
Java – jmustache
<span class="todo-count"><sturdy>{{activeItemsCount}}</sturdy> objects left</span>
The above change within the template requires a supporting technique within the mannequin:
Go
sort Merchandise struct {
Title string
IsCompleted bool
}
sort Listing struct {
Gadgets []*Merchandise
}
func (l *Listing) ActiveItems() []*Merchandise {
var consequence []*Merchandise
for _, merchandise := vary l.Gadgets {
if !merchandise.IsCompleted {
consequence = append(consequence, merchandise)
}
}
return consequence
}
Java
public class TodoList {
non-public remaining Listing<TodoItem> objects = new ArrayList<>();
// ...
public lengthy activeItemsCount() {
return objects.stream().filter(TodoItem::isActive).depend();
}
}
We have invested a bit effort in our testing infrastructure, in order that including new
take a look at instances is less complicated. Within the subsequent part, we’ll see that the necessities
for the subsequent take a look at instances will push us to refine our take a look at infrastructure additional.
Making the desk extra expressive, on the expense of the take a look at code
We are going to now take a look at the “All”, “Lively” and “Accomplished” navigation hyperlinks at
the underside of the UI (see the image above),
and these rely on which url we’re visiting, which is
one thing that our template has no approach to discover out.
At present, all we go to our template is our mannequin, which is a todo-list.
It isn’t appropriate so as to add the presently visited url to the mannequin, as a result of that’s
consumer navigation state, not utility state.
So we have to go extra info to the template past the mannequin. A simple means
is to go a map, which we assemble in our
renderTemplate
operate:
Go
func renderTemplate(mannequin *todo.Listing, path string) bytes.Buffer { templ := template.Should(template.ParseFiles("index.tmpl")) var buf bytes.Buffer knowledge := map[string]any{ "mannequin": mannequin, "path": path, } err := templ.Execute(&buf, knowledge) if err != nil { panic(err) } return buf }
Java
non-public String renderTemplate(String templateName, TodoList mannequin, String path) { var template = Mustache.compiler().compile( new InputStreamReader( getClass().getResourceAsStream(templateName))); var knowledge = Map.of( "mannequin", mannequin, "path", path ); return template.execute(knowledge); }
And correspondingly our take a look at instances desk has yet one more discipline:
Go
var testCases = []struct { identify string mannequin *todo.Listing path string selector string matches []string }{ { identify: "all todo objects are proven", mannequin: todo.NewList(). Add("Foo"). Add("Bar"), selector: "ul.todo-list li", matches: []string{"Foo", "Bar"}, }, // ... the opposite instances { identify: "highlighted navigation hyperlink: All", path: "/", selector: "ul.filters a.chosen", matches: []string{"All"}, }, { identify: "highlighted navigation hyperlink: Lively", path: "/energetic", selector: "ul.filters a.chosen", matches: []string{"Lively"}, }, { identify: "highlighted navigation hyperlink: Accomplished", path: "/accomplished", selector: "ul.filters a.chosen", matches: []string{"Accomplished"}, }, }
Java
report TestCase(String identify, TodoList mannequin, String path, String selector, Listing<String> matches) { @Override public String toString() { return identify; } } public static TestCase[] indexTestCases() { return new TestCase[]{ new TestCase( "all todo objects are proven", new TodoList() .add("Foo") .add("Bar"), "/", "ul.todo-list li", Listing.of("Foo", "Bar")), // ... the earlier instances new TestCase( "highlighted navigation hyperlink: All", new TodoList(), "/", "ul.filters a.chosen", Listing.of("All")), new TestCase( "highlighted navigation hyperlink: Lively", new TodoList(), "/energetic", "ul.filters a.chosen", Listing.of("Lively")), new TestCase( "highlighted navigation hyperlink: Accomplished", new TodoList(), "/accomplished", "ul.filters a.chosen", Listing.of("Accomplished")), }; }
We discover that for the three new instances, the mannequin is irrelevant;
whereas for the earlier instances, the trail is irrelevant. The Go syntax permits us
to initialize a struct with simply the fields we’re curious about, however Java doesn’t have
the same characteristic, so we’re pushed to go additional info, and this makes the take a look at instances
desk more durable to know.
A developer may take a look at the primary take a look at case and surprise if the anticipated habits relies upon
on the trail being set to “/”
, and could be tempted so as to add extra instances with
a distinct path. In the identical means, when studying the
highlighted navigation hyperlink take a look at instances, the developer may surprise if the
anticipated habits relies on the mannequin being set to an empty todo record. In that case, one may
be led so as to add irrelevant take a look at instances for the highlighted hyperlink with non-empty todo-lists.
We need to optimize for the time of the builders, so it is worthwhile to keep away from including irrelevant
knowledge to our take a look at case. In Java we’d go null
for the
irrelevant fields, however there’s a greater means: we will use
the builder sample,
popularized by Joshua Bloch.
We are able to rapidly write one for the Java TestCase
report this manner:
Java
report TestCase(String identify,
TodoList mannequin,
String path,
String selector,
Listing<String> matches) {
@Override
public String toString() {
return identify;
}
public static remaining class Builder {
String identify;
TodoList mannequin;
String path;
String selector;
Listing<String> matches;
public Builder identify(String identify) {
this.identify = identify;
return this;
}
public Builder mannequin(TodoList mannequin) {
this.mannequin = mannequin;
return this;
}
public Builder path(String path) {
this.path = path;
return this;
}
public Builder selector(String selector) {
this.selector = selector;
return this;
}
public Builder matches(String ... matches) {
this.matches = Arrays.asList(matches);
return this;
}
public TestCase construct() {
return new TestCase(identify, mannequin, path, selector, matches);
}
}
}
Hand-coding builders is a bit tedious, however doable, although there are
automated methods to jot down them.
Now we will rewrite our Java take a look at instances with the Builder
, to
obtain higher readability:
Java
public static TestCase[] indexTestCases() { return new TestCase[]{ new TestCase.Builder() .identify("all todo objects are proven") .mannequin(new TodoList() .add("Foo") .add("Bar")) .selector("ul.todo-list li") .matches("Foo", "Bar") .construct(), // ... different instances new TestCase.Builder() .identify("highlighted navigation hyperlink: Accomplished") .path("/accomplished") .selector("ul.filters a.chosen") .matches("Accomplished") .construct(), }; }
So, the place are we with our assessments? At current, they fail for the improper purpose: null-pointer exceptions
as a result of lacking mannequin
and path
values.
To be able to get our new take a look at instances to fail for the precise purpose, specifically that the template does
not but have logic to spotlight the proper hyperlink, we should
present default values for mannequin
and path
. In Go, we will do that
within the take a look at technique:
Go
func Test_indexTemplate(t *testing.T) {
for _, take a look at := vary testCases {
t.Run(take a look at.identify, func(t *testing.T) {
if take a look at.mannequin == nil {
take a look at.mannequin = todo.NewList()
}
buf := renderTemplate(take a look at.mannequin, take a look at.path)
// ... identical as earlier than
})
}
}
In Java, we will present default values within the builder:
Java
public static remaining class Builder { String identify; TodoList mannequin = new TodoList(); String path = "/"; String selector; Listing<String> matches; // ... }
With these adjustments, we see that the final two take a look at instances, those for the highlighted hyperlink Lively
and Accomplished fail, for the anticipated purpose that the highlighted hyperlink doesn’t change:
Go
=== RUN Test_indexTemplate/highlighted_navigation_link:_Active index_template_test.go:82: Error Hint: .../tdd-templates/go/index_template_test.go:82 Error: Not equal: anticipated: "Lively" precise : "All" === RUN Test_indexTemplate/highlighted_navigation_link:_Completed index_template_test.go:82: Error Hint: .../tdd-templates/go/index_template_test.go:82 Error: Not equal: anticipated: "Accomplished" precise : "All"
Java
IndexTemplateTest > testIndexTemplate(TestCase) > [5] highlighted navigation hyperlink: Lively FAILED org.opentest4j.AssertionFailedError: Anticipating: <"All"> to be equal to: <"Lively"> however was not. IndexTemplateTest > testIndexTemplate(TestCase) > [6] highlighted navigation hyperlink: Accomplished FAILED org.opentest4j.AssertionFailedError: Anticipating: <"All"> to be equal to: <"Accomplished"> however was not.
To make the assessments go, we make these adjustments to the template:
Go
<ul class="filters"> <li> <a class="{{ if eq .path "/" }}chosen{{ finish }}" href="#/">All</a> </li> <li> <a class="{{ if eq .path "/energetic" }}chosen{{ finish }}" href="#/energetic">Lively</a> </li> <li> <a class="{{ if eq .path "/accomplished" }}chosen{{ finish }}" href="#/accomplished">Accomplished</a> </li> </ul>
Java – jmustache
<ul class="filters"> <li> <a class="{{ #pathRoot }}chosen{{ /pathRoot }}" href="#/">All</a> </li> <li> <a class="{{ #pathActive }}chosen{{ /pathActive }}" href="#/energetic">Lively</a> </li> <li> <a class="{{ #pathCompleted }}chosen{{ /pathCompleted }}" href="#/accomplished">Accomplished</a> </li> </ul>
For the reason that Mustache template language doesn’t permit for equality testing, we should change the
knowledge handed to the template in order that we execute the equality assessments earlier than rendering the template:
Java
non-public String renderTemplate(String templateName, TodoList mannequin, String path) { var template = Mustache.compiler().compile( new InputStreamReader( getClass().getResourceAsStream(templateName))); var knowledge = Map.of( "mannequin", mannequin, "pathRoot", path.equals("/"), "pathActive", path.equals("/energetic"), "pathCompleted", path.equals("/accomplished") ); return template.execute(knowledge); }
And with these adjustments, all of our assessments now go.
To recap this part, we made the take a look at code a bit bit extra sophisticated, in order that the take a look at
instances are clearer: this can be a excellent tradeoff!
Degree 3: testing HTML behaviour
Within the story up to now, we examined the behaviour of the HTML
templates, by checking the construction of the generated HTML.
That is good, however what if we wished to check the behaviour of the HTML
itself, plus any CSS and JavaScript it could use?
The behaviour of HTML by itself is normally fairly apparent, as a result of
there’s not a lot of it. The one parts that may work together with the
consumer are the anchor (<a>
), <type>
and
<enter>
parts, however the image adjustments utterly when
we add CSS, that may disguise, present, transfer round issues and much extra, and
with JavaScript, that may add any behaviour to a web page.
In an utility that’s primarily rendered server-side, we anticipate
that the majority behaviour is carried out by returning new HTML with a
round-trip to the consumer, and this may be examined adequately with the
strategies we have seen up to now, however what if we wished to hurry up the
utility behaviour with a library reminiscent of HTMX? This library works by particular
attributes which can be added to parts so as to add Ajax behaviour. These
attributes are in impact a DSL that we’d need to
take a look at.
How can we take a look at the mix of HTML, CSS and JavaScript in
a unit take a look at?
Testing HTML, CSS and JavaScript requires one thing that is ready to
interpret and execute their behaviours; in different phrases, we want a
browser! It’s customary to make use of headless browsers in end-to-end assessments;
can we use them for unitary assessments as an alternative? I believe that is doable,
utilizing the next strategies, though I need to admit I’ve but to attempt
this on an actual challenge.
We are going to use the Playwright
library, that’s obtainable for each Go and
Java. The assessments we
are going to jot down will likely be slower, as a result of we must wait just a few
seconds for the headless browser to begin, however will retain a few of the
vital traits of unit assessments, primarily that we’re testing
simply the HTML (and any related CSS and JavaScript), in isolation from
another server-side logic.
Persevering with with the TodoMVC
instance, the subsequent factor we’d need to take a look at is what occurs when the
consumer clicks on the checkbox of a todo merchandise. What we might prefer to occur is
that:
- A POST name to the server is made, in order that the appliance is aware of
that the state of a todo merchandise has modified - The server returns new HTML for the dynamic a part of the web page,
specifically all the part with class “todoapp”, in order that we will present the
new state of the appliance together with the depend of remaining “energetic”
objects (see the template above) - The web page replaces the previous contents of the “todoapp” part with
the brand new ones.
Loading the web page within the Playwright browser
We begin with a take a look at that can simply load the preliminary HTML. The take a look at
is a bit concerned, so I present the entire code right here, after which I’ll
remark it little by little.
Go
func Test_toggleTodoItem(t *testing.T) { // render the preliminary HTML mannequin := todo.NewList(). Add("One"). Add("Two") initialHtml := renderTemplate("index.tmpl", mannequin, "/") // open the browser web page with Playwright web page := openPage() defer web page.Shut() logActivity(web page) // stub community calls err := web page.Route("**", func(route playwright.Route) { if route.Request().URL() == "http://localhost:4567/index.html" { // serve the preliminary HTML stubResponse(route, initialHtml.String(), "textual content/html") } else { // keep away from sudden requests panic("sudden request: " + route.Request().URL()) } }) if err != nil { t.Deadly(err) } // load preliminary HTML within the web page response, err := web page.Goto("http://localhost:4567/index.html") if err != nil { t.Deadly(err) } if response.Standing() != 200 { t.Fatalf("sudden standing: %d", response.Standing()) } }
Java
public class IndexBehaviourTest { static Playwright playwright; static Browser browser; @BeforeAll static void launchBrowser() { playwright = Playwright.create(); browser = playwright.chromium().launch(); } @AfterAll static void closeBrowser() { playwright.shut(); } @Check void toggleTodoItem() { // Render the preliminary html TodoList mannequin = new TodoList() .add("One") .add("Two"); String initialHtml = renderTemplate("/index.tmpl", mannequin, "/"); attempt (Web page web page = browser.newPage()) { logActivity(web page); // stub community calls web page.route("**", route -> { if (route.request().url().equals("http://localhost:4567/index.html")) { // serve the preliminary HTML route.fulfill(new Route.FulfillOptions() .setContentType("textual content/html") .setBody(initialHtml)); } else { // we do not need sudden calls fail(String.format("Surprising request: %s %s", route.request().technique(), route.request().url())); } }); // load preliminary html web page.navigate("http://localhost:4567/index.html"); } } }
Firstly of the take a look at, we initialize the mannequin with two todo
objects “One” and “Two”, then we render the template as earlier than:
Go
mannequin := todo.NewList(). Add("One"). Add("Two") initialHtml := renderTemplate("index.tmpl", mannequin, "/")
Java
TodoList mannequin = new TodoList() .add("One") .add("Two"); String initialHtml = renderTemplate("/index.tmpl", mannequin, "/");
Then we open the Playwright “web page”, which is able to begin a headless
browser
Go
web page := openPage() defer web page.Shut() logActivity(web page)
Java
attempt (Web page web page = browser.newPage()) { logActivity(web page);
The openPage
operate in Go returns a Playwright
Web page
object,
Go
func openPage() playwright.Web page { pw, err := playwright.Run() if err != nil { log.Fatalf("couldn't begin playwright: %v", err) } browser, err := pw.Chromium.Launch() if err != nil { log.Fatalf("couldn't launch browser: %v", err) } web page, err := browser.NewPage() if err != nil { log.Fatalf("couldn't create web page: %v", err) } return web page }
and the logActivity
operate gives suggestions on what
the web page is doing
Go
func logActivity(web page playwright.Web page) { web page.OnRequest(func(request playwright.Request) { log.Printf(">> %s %sn", request.Methodology(), request.URL()) }) web page.OnResponse(func(response playwright.Response) { log.Printf("<< %d %sn", response.Standing(), response.URL()) }) web page.OnLoad(func(web page playwright.Web page) { log.Println("Loaded: " + web page.URL()) }) web page.OnConsole(func(message playwright.ConsoleMessage) { log.Println("! " + message.Textual content()) }) }
Java
non-public void logActivity(Web page web page) { web page.onRequest(request -> System.out.printf(">> %s %spercentn", request.technique(), request.url())); web page.onResponse(response -> System.out.printf("<< %s %spercentn", response.standing(), response.url())); web page.onLoad(page1 -> System.out.println("Loaded: " + page1.url())); web page.onConsoleMessage(consoleMessage -> System.out.println("! " + consoleMessage.textual content())); }
Then we stub all community exercise that the web page may attempt to do
Go
err := web page.Route("**", func(route playwright.Route) {
if route.Request().URL() == "http://localhost:4567/index.html" {
// serve the preliminary HTML
stubResponse(route, initialHtml.String(), "textual content/html")
} else {
// keep away from sudden requests
panic("sudden request: " + route.Request().URL())
}
})
Java
// stub community calls
web page.route("**", route -> {
if (route.request().url().equals("http://localhost:4567/index.html")) {
// serve the preliminary HTML
route.fulfill(new Route.FulfillOptions()
.setContentType("textual content/html")
.setBody(initialHtml));
} else {
// we do not need sudden calls
fail(String.format("Surprising request: %s %s", route.request().technique(), route.request().url()));
}
});
and we ask the web page to load the preliminary HTML
Go
response, err := web page.Goto("http://localhost:4567/index.html")
Java
web page.navigate("http://localhost:4567/index.html");
With all this equipment in place, we run the take a look at; it succeeds and
it logs the stubbed community exercise on commonplace output:
Go
=== RUN Test_toggleTodoItem >> GET http://localhost:4567/index.html << 200 http://localhost:4567/index.html Loaded: http://localhost:4567/index.html --- PASS: Test_toggleTodoItem (0.89s)
Java
IndexBehaviourTest > toggleTodoItem() STANDARD_OUT >> GET http://localhost:4567/index.html << 200 http://localhost:4567/index.html Loaded: http://localhost:4567/index.html IndexBehaviourTest > toggleTodoItem() PASSED
So with this take a look at we at the moment are in a position to load arbitrary HTML in a
headless browser. Within the subsequent sections we’ll see find out how to simulate consumer
interplay with parts of the web page, and observe the web page’s
behaviour. However first we have to remedy an issue with the dearth of
identifiers in our area mannequin.
Figuring out todo objects
Now we need to click on on the “One” checkbox. The issue we’ve is
that at current, we’ve no approach to establish particular person todo objects, so
we introduce an Id
discipline within the todo merchandise:
Go – up to date mannequin with Id
sort Merchandise struct { Id int Title string IsCompleted bool } func (l *Listing) AddWithId(id int, title string) *Listing { merchandise := Merchandise{ Id: id, Title: title, } l.Gadgets = append(l.Gadgets, &merchandise) return l } // Add creates a brand new todo.Merchandise with a random Id func (l *Listing) Add(title string) *Listing { merchandise := Merchandise{ Id: generateRandomId(), Title: title, } l.Gadgets = append(l.Gadgets, &merchandise) return l } func generateRandomId() int { return abs(rand.Int()) }
Java – up to date mannequin with Id
public class TodoList { non-public remaining Listing<TodoItem> objects = new ArrayList<>(); public TodoList add(String title) { objects.add(new TodoItem(generateRandomId(), title, false)); return this; } public TodoList addCompleted(String title) { objects.add(new TodoItem(generateRandomId(), title, true)); return this; } public TodoList add(int id, String title) { objects.add(new TodoItem(id, title, false)); return this; } non-public static int generateRandomId() { return new Random().nextInt(0, Integer.MAX_VALUE); } } public report TodoItem(int id, String title, boolean isCompleted) { public boolean isActive() { return !isCompleted; } }
And we replace the mannequin in our take a look at so as to add specific Ids
Go – including Id within the take a look at knowledge
func Test_toggleTodoItem(t *testing.T) { // render the preliminary HTML mannequin := todo.NewList(). AddWithId(101, "One"). AddWithId(102, "Two") initialHtml := renderTemplate("index.tmpl", mannequin, "/") // ... }
Java – including Id within the take a look at knowledge
@Check void toggleTodoItem() { // Render the preliminary html TodoList mannequin = new TodoList() .add(101, "One") .add(102, "Two"); String initialHtml = renderTemplate("/index.tmpl", mannequin, "/"); }
We at the moment are prepared to check consumer interplay with the web page.
Clicking on a todo merchandise
We need to simulate consumer interplay with the HTML web page. It could be
tempting to proceed to make use of CSS selectors to establish the particular
checkbox that we need to click on, however there’s a greater means: there’s a
consensus amongst front-end builders that one of the best ways to check
interplay with a web page is to make use of it
the identical means that customers do. As an example, you do not search for a
button by a CSS locator reminiscent of button.purchase
; as an alternative,
you search for one thing clickable with the label “Purchase”. In observe,
this implies figuring out components of the web page by their
ARIA roles.
To this finish, we add code to our take a look at to search for a checkbox labelled
“One”:
Go
func Test_toggleTodoItem(t *testing.T) { // ... // click on on the "One" checkbox checkbox := web page.GetByRole(*playwright.AriaRoleCheckbox, playwright.PageGetByRoleOptions{Title: "One"}) if err := checkbox.Click on(); err != nil { t.Deadly(err) } }
Java
@Check void toggleTodoItem() { // ... // click on on the "One" checkbox var checkbox = web page.getByRole(AriaRole.CHECKBOX, new Web page.GetByRoleOptions().setName("One")); checkbox.click on(); } }
We run the take a look at, and it fails:
Go
>> GET http://localhost:4567/index.html
<< 200 http://localhost:4567/index.html
Loaded: http://localhost:4567/index.html
--- FAIL: Test_toggleTodoItem (32.74s)
index_behaviour_test.go:50: playwright: timeout: Timeout 30000ms exceeded.
Java
IndexBehaviourTest > toggleTodoItem() STANDARD_OUT
>> GET http://localhost:4567/index.html
<< 200 http://localhost:4567/index.html
Loaded: http://localhost:4567/index.html
IndexBehaviourTest > toggleTodoItem() FAILED
com.microsoft.playwright.TimeoutError: Error {
message="hyperlink the label to the checkbox correctly:
generated HTML with unhealthy accessibility
<li>
<div class="view">
<enter class="toggle" sort="checkbox">
<label>One</label>
<button class="destroy"></button>
</div>
</li>
We repair it through the use of the for
attribute within the
template,
index.tmpl – Go
<li>
<div class="view">
<enter id="checkbox-{{.Id}}" class="toggle" sort="checkbox">
<label for="checkbox-{{.Id}}">{{.Title}}</label>
<button class="destroy"></button>
</div>
</li>
index.tmpl – Java
<li>
<div class="view">
<enter id="checkbox-{{ id }}" class="toggle" sort="checkbox">
<label for="checkbox-{{ id }}">{{ title }}</label>
<button class="destroy"></button>
</div>
</li>
In order that it generates correct, accessible HTML:
generated HTML with higher accessibility
<li>
<div class="view">
<enter id="checkbox-101" class="toggle" sort="checkbox">
<label for="checkbox-101">One</label>
<button class="destroy"></button>
</div>
</li>
We run once more the take a look at, and it passes.
On this part we noticed how testing the HTML in the identical was as customers
work together with it led us to make use of ARIA roles, which led to bettering
accessibility of our generated HTML. Within the subsequent part, we are going to see
find out how to take a look at that the clicking on a todo merchandise triggers a distant name to the
server, that ought to lead to swapping part of the present HTML with
the HTML returned by the XHR name.
Spherical-trip to the server
Now we are going to lengthen our take a look at. We inform the take a look at that if name to
POST /toggle/101
is obtained, it ought to return some
stubbed HTML.
Go
} else if route.Request().URL() == "http://localhost:4567/toggle/101" && route.Request().Methodology() == "POST" { // we anticipate {that a} POST /toggle/101 request is made once we click on on the "One" checkbox const stubbedHtml = ` <part class="todoapp"> <p>Stubbed html</p> </part>` stubResponse(route, stubbedHtml, "textual content/html")
Java
} else if (route.request().url().equals("http://localhost:4567/toggle/101") && route.request().technique().equals("POST")) { // we anticipate {that a} POST /toggle/101 request is made once we click on on the "One" checkbox String stubbedHtml = """ <part class="todoapp"> <p>Stubbed html</p> </part> """; route.fulfill(new Route.FulfillOptions() .setContentType("textual content/html") .setBody(stubbedHtml));
And we stub the loading of the HTMX library, which we load from a
native file:
Go
} else if route.Request().URL() == "https://unpkg.com/[email protected]" {
// serve the htmx library
stubResponse(route, readFile("testdata/htmx.min.js"), "utility/javascript")
Go
} else if (route.request().url().equals("https://unpkg.com/[email protected]")) {
// serve the htmx library
route.fulfill(new Route.FulfillOptions()
.setContentType("textual content/html")
.setBody(readFile("/htmx.min.js")));
Lastly, we add the expectation that, after we click on the checkbox,
the part of the HTML that incorporates a lot of the utility is
reloaded.
Go
// click on on the "One" checkbox checkbox := web page.GetByRole(*playwright.AriaRoleCheckbox, playwright.PageGetByRoleOptions{Title: "One"}) if err := checkbox.Click on(); err != nil { t.Deadly(err) } // examine that the web page has been up to date doc := parseHtml(t, content material(t, web page)) parts := doc.Discover("physique > part.todoapp > p") assert.Equal(t, "Stubbed html", parts.Textual content(), should(web page.Content material()))
java
// click on on the "One" checkbox var checkbox = web page.getByRole(AriaRole.CHECKBOX, new Web page.GetByRoleOptions().setName("One")); checkbox.click on(); // examine that the web page has been up to date var doc = parseHtml(web page.content material()); var parts = doc.choose("physique > part.todoapp > p"); assertThat(parts.textual content()) .describedAs(web page.content material()) .isEqualTo("Stubbed html");
We run the take a look at, and it fails, as anticipated. To be able to perceive
why precisely it fails, we add to the error message the entire HTML
doc.
Go
assert.Equal(t, "Stubbed html", parts.Textual content(), should(web page.Content material()))
Java
assertThat(parts.textual content())
.describedAs(web page.content material())
.isEqualTo("Stubbed html");
The error message may be very verbose, however we see that the rationale it
fails is that we do not see the stubbed HTML within the output. This implies
that the web page didn’t make the anticipated XHR name.
Go – Java is analogous
--- FAIL: Test_toggleTodoItem (2.75s) === RUN Test_toggleTodoItem >> GET http://localhost:4567/index.html << 200 http://localhost:4567/index.html Loaded: http://localhost:4567/index.html index_behaviour_test.go:67: Error Hint: .../index_behaviour_test.go:67 Error: Not equal: anticipated: "Stubbed html" precise : "" ... Check: Test_toggleTodoItem Messages: <!DOCTYPE html><html lang="en"><head> <meta charset="utf-8"> <meta identify="viewport" content material="width=device-width, initial-scale=1"> <title>Template • TodoMVC</title> <script src="https://unpkg.com/[email protected]"></script> <physique> <part class="todoapp"> ... <li class=""> <div class="view"> <enter id="checkbox-101" class="toggle" sort="checkbox"> <label for="checkbox-101">One</label> <button class="destroy"></button> </div> </li> ...
We are able to make this take a look at go by altering the HTML template to make use of HTMX
to make an XHR name again to the server. First we load the HTMX
library:
index.tmpl
<title>Template • TodoMVC</title>
<script src="https://unpkg.com/[email protected]"></script>
Then we add the HTMX attributes to the checkboxes:
index.tmpl
<enter data-hx-post="/toggle/{{.Id}}" data-hx-target="part.todoapp" id="checkbox-{{.Id}}" class="toggle" sort="checkbox">
The data-hx-post
annotation will make HTMX do a POST
name to the required url. The data-hx-target
tells HTMX
to repeat the HTML returned by the decision, to the aspect specified by the
part.todoapp
CSS locator.
We run once more the take a look at, and it nonetheless fails!
Go – Java is analogous
--- FAIL: Test_toggleTodoItem (2.40s) === RUN Test_toggleTodoItem >> GET http://localhost:4567/index.html << 200 http://localhost:4567/index.html >> GET https://unpkg.com/[email protected] << 200 https://unpkg.com/[email protected] Loaded: http://localhost:4567/index.html >> POST http://localhost:4567/toggle/101 << 200 http://localhost:4567/toggle/101 index_behaviour_test.go:67: Error Hint: .../index_behaviour_test.go:67 Error: Not equal: anticipated: "Stubbed html" precise : "" ... Check: Test_toggleTodoItem Messages: <!DOCTYPE html><html lang="en"><head> <meta charset="utf-8"> <meta identify="viewport" content material="width=device-width, initial-scale=1"> <title>Template • TodoMVC</title> <script src="https://unpkg.com/[email protected]"></script> ... <physique> <part class="todoapp"><part class="todoapp"> <p>Stubbed html</p> </part></part> ... </physique></html>
The log strains present that the POST name occurred as anticipated, however
examination of the error message reveals that the HTML construction we
anticipated shouldn’t be there: we’ve a part.todoapp
nested
inside one other. Because of this we’re not utilizing the HTMX annotations
appropriately, and reveals why this sort of take a look at might be priceless. We add the
lacking annotation
index.tmpl
<enter
data-hx-post="/toggle/{{.Id}}"
data-hx-target="part.todoapp"
data-hx-swap="outerHTML"
id="checkbox-{{.Id}}"
class="toggle"
sort="checkbox">
The default behaviour of HTMX is to exchange the interior HTML of the
goal aspect. The data-hx-swap=”outerHTML”
annotation
tells HTMX to exchange the outer HTML as an alternative.
and we take a look at once more, and this time it passes!
Go
=== RUN Test_toggleTodoItem >> GET http://localhost:4567/index.html << 200 http://localhost:4567/index.html >> GET https://unpkg.com/[email protected] << 200 https://unpkg.com/[email protected] Loaded: http://localhost:4567/index.html >> POST http://localhost:4567/toggle/101 << 200 http://localhost:4567/toggle/101 --- PASS: Test_toggleTodoItem (1.39s)
Java
IndexBehaviourTest > toggleTodoItem() STANDARD_OUT >> GET http://localhost:4567/index.html << 200 http://localhost:4567/index.html >> GET https://unpkg.com/[email protected] << 200 https://unpkg.com/[email protected] Loaded: http://localhost:4567/index.html >> POST http://localhost:4567/toggle/101 << 200 http://localhost:4567/toggle/101 IndexBehaviourTest > toggleTodoItem() PASSED
On this part we noticed find out how to write a take a look at for the behaviour of our
HTML that, whereas utilizing the sophisticated equipment of a headless browser,
nonetheless feels extra like a unit take a look at than an integration take a look at. It’s in
truth testing simply an HTML web page with any related CSS and JavaScript,
in isolation from different components of the appliance reminiscent of controllers,
providers or repositories.
The take a look at prices 2-3 seconds of ready time for the headless browser to come back up, which is normally an excessive amount of for a unit take a look at; nonetheless, like a unit take a look at, it is extremely secure, as it isn’t flaky, and its failures are documented with a comparatively clear error message.
See the ultimate model of the take a look at in Go and in Java.
Bonus degree: Stringly asserted
Esko Luontola, TDD knowledgeable and creator of the net course tdd.mooc.fi, steered another to testing HTML with CSS selectors: the concept is to remodel HTML right into a human-readable canonical type.
Let’s take for instance this snippet of generated HTML:
<ul class="todo-list"> <li class=""> <div class="view"> <enter id="checkbox-100" class="toggle" sort="checkbox"> <label for="checkbox-100">One</label> <button class="destroy"></button> </div> </li> <li class=""> <div class="view"> <enter id="checkbox-200" class="toggle" sort="checkbox"> <label for="checkbox-200">Two</label> <button class="destroy"></button> </div> </li> <li class="accomplished"> <div class="view"> <enter id="checkbox-300" class="toggle" sort="checkbox"> <label for="checkbox-300">Three</label> <button class="destroy"></button> </div> </li> </ul>
We may visualize the above HTML by:
- deleting all HTML tags
- lowering each sequence of whitespace characters to a single clean
to reach at:
One Two Three
This, nonetheless, removes an excessive amount of of the HTML construction to be helpful. As an example, it doesn’t allow us to distinguish between energetic and accomplished objects. Some HTML aspect signify seen content material: as an example
<enter worth="foo" />
reveals a textual content field with the phrase “foo” that is a vital a part of the means we understand HTML. To visualise these parts, Esko suggests so as to add a data-test-icon
attribute that provides some textual content for use instead of the aspect when visualizing it for testing. With this,
<enter worth="foo" data-test-icon="[foo]" />
the enter aspect is visualized as [foo]
, with the sq. brackets hinting that the phrase “foo” sits inside an editable textual content field. Now if we add test-icons to our HTML template,
Go — Java is analogous
<ul class="todo-list"> {{ vary .mannequin.AllItems }} <li class="{{ if .IsCompleted }}accomplished{{ finish }}"> <div class="view"> <enter data-hx-post="/toggle/{{ .Id }}" data-hx-target="part.todoapp" data-hx-swap="outerHTML" id="checkbox-{{ .Id }}" class="toggle" sort="checkbox" data-test-icon="{{ if .IsCompleted }}✅{{ else }}⬜{{ finish }}"> <label for="checkbox-{{ .Id }}">{{ .Title }}</label> <button class="destroy" data-test-icon="❌️"></button> </div> </li> {{ finish }} </ul>
we will assert towards its canonical visible illustration like this:
Go
func Test_visualize_html_example(t *testing.T) { mannequin := todo.NewList(). Add("One"). Add("Two"). AddCompleted("Three") buf := renderTemplate("todo-list.tmpl", mannequin, "/") anticipated := ` ⬜ One ❌️ ⬜ Two ❌️ ✅ Three ❌️ ` assert.Equal(t, normalizeWhitespace(anticipated), visualizeHtml(buf.String())) }
Java
@Check void visualize_html_example() { var mannequin = new TodoList() .add("One") .add("Two") .addCompleted("Three"); var html = renderTemplate("/todo-list.tmpl", mannequin, "/"); assertThat(visualizeHtml(html)) .isEqualTo(normalizeWhitespace(""" ⬜ One ❌️ ⬜ Two ❌️ ✅ Three ❌️ """)); }
Right here is Esko Luontola’s Java implementation of the 2 capabilities that make this doable, and my translation to Go of his code.
Go
func visualizeHtml(html string) string sturdy func normalizeWhitespace(s string) string { return strings.TrimSpace(replaceAll(s, "s+", " ")) } func replaceAll(src, regex, repl string) string { re := regexp.MustCompile(regex) return re.ReplaceAllString(src, repl) }
Java
public static String visualizeHtml(String html) span public static String normalizeWhitespace(String s) { return s.replaceAll("s+", " ").trim(); }
On this part, we’ve seen a method for asserting HTML content material that’s an alternative choice to the CSS selector-based method utilized in the remainder of the article. Esko Luontola has reported nice success with it, and I hope readers have success with it too!
This method of asserting towards giant, sophisticated knowledge buildings reminiscent of HTML pages by lowering them to a canonical string model has no identify that I do know of. Martin Fowler steered “stringly asserted”, and from his suggestion comes the identify of this part.