236 lines
8.0 KiB
Plaintext
236 lines
8.0 KiB
Plaintext
include ../../../../_includes/_util-fns
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:markdown
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We’ll write our tests with the [Jasmine test framework](http://jasmine.github.io/2.3/introduction.html).
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We’ll start by getting *some* tests to work - *any* tests at all.
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We will learn
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- basic Jasmine testing skills
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- to run our tests in the browser
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- to write simple Jasmine tests in TypeScript
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- to debug a test in the browser
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**Create a new project folder** perhaps called `angular2-unit-testing`.
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.l-main-section
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:markdown
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## Install npm packages locally
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Next follow all of the steps prescribed in “Install npm packages locally” of the
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[QuickStart](../quickstart.html).
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We’ll also add the Jasmine package via `npm`:
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pre.prettyprint.lang-bash
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code npm install jasmine-core --save-dev --save-exact
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.alert.is-important
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:markdown
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Be sure to install `jasmine-core` , not `jasmine`!
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:markdown
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**Create a sub-folder `src` ** for our tests and then **cd into it**.
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We are going to **display and control our tests in the browser**.
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.l-sub-section
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:markdown
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The browser is nice during development of a few tests. It’s not the best venue for working with a lot of tests and it won’t do at all for build automation. We’ll switch to the karma test-runner when the time comes. But the browser will do for now.
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:markdown
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Create a new file called`unit-tests.html` and enter the following:
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```
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<html>
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<head>
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<title>1st Jasmine Tests</title>
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<link rel="stylesheet" href="../node_modules/jasmine/lib/jasmine.css">
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<script src="../node_modules/jasmine/lib/jasmine.js"></script>
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<script src="../node_modules/jasmine/lib/jasmine-html.js"></script>
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<script src="../node_modules/jasmine/lib/boot.js"></script>
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</head>
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<body>
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</body>
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</html>
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```
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In the head we have three Jasmine scripts and one Jasmine css file. That’s the foundation for running any tests.
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We’ll write our first test with inline JavaScript inside the body tag:
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```
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<script>
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it('true is true', function(){ expect(true).toEqual(true); });
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</script>
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```
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Now open `unit-tests.html` in a browser and see the Jasmine HTML test output:
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figure.image-display
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img(src='/resources/images/devguide/jasmine-testing-101/jasmine-1-spec-0-failures.png' style="height:170px;" alt="Jasmine HTML test output")
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:markdown
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It doesn’t get much simpler than that!
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.l-main-section
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:markdown
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## First TypeScript Test
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Perhaps too simple. We won’t write our entire test suite inside one HTML file.
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Let’s **extract** that line of test code to a **new file in `src` called `1st.spec.ts` ** .
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.l-sub-section
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:markdown
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Among Jasmine developers, a test is known as a “spec” and test filenames include the word “spec”. We’ll stick with that convention.
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:markdown
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The test we wrote is valid TypeScript because any JavaScript is valid TypeScript. But let’s make it more modern with an arrow function:
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```
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it('true is true', () => expect(true).toEqual(true));
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```
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Now modify `unit-tests.html` to load the script:
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```
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<script src="1st.spec.js"></script>
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```
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Hold on! We wrote a TypeScript file but we’re loading a JavaScript file?
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That’s a reminder that we need to compile our TypeScript test files as we do our TypeScript application files. Do that next.
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.l-main-section
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:markdown
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## Prepare for TypeScript
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As we’ve seen before, we first have to tell the compiler how to compile our TypeScript files with
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a ** `tsconfig.json` **.
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We can copy one from an application we wrote previously and paste it into our src sub-folder.
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It should look something like this:
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```
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{
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"compilerOptions": {
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"target": "ES5",
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"module": "commonjs",
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"sourceMap": true,
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"emitDecoratorMetadata": true,
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"experimentalDecorators": true
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}
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}
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```
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## Compile and Run
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Compile in the terminal window using the npm script command
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pre.prettyprint.lang-bash
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code npm run tsc
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.alert.is-helpful
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:markdown
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Our editor and the compiler may complain that they don’t know
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what `it` and `expect` are because they lack the typing files that describe Jasmine.
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We can ignore those annoying complaints for now as they are harmless.
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:markdown
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If we reload the browser, we should see the same Jasmine test-runner output as before.
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We’ll be evolving these tests rapidly and it would be nice to have the browser refresh automatically as we make changes and recompile.
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Let’s launch with **live-server** in a second terminal window:
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pre.prettyprint.lang-bash
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code npm start
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:markdown
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Now navigate to `1st-tests.html`
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We should get the same Jasmine test-runner output as before.
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.l-main-section
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:markdown
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## Add a describe and another test
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We can’t tell what file produced these test results. We only have one file at the moment but soon we’ll write more.
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We should wrap this test something that identifies the file. In Jasmine that “something” is a `describe` function. Every test file should have at least one `describe` that identifies the file holding the test(s).
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Here’s what our revised `1st.spec.ts` looks like when wrapped in a `describe`:
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```
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describe('1st tests', () => {
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it('true is true', () => expect(true).toEqual(true));
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});
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```
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And here’s how the test report displays it.
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figure.image-display
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img(src='/resources/images/devguide/jasmine-testing-101/test-report-1-spec-0-failures.png' style="height:100px;" alt="1 spec, 0 failures")
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:markdown
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Let’s add another Jasmine test to `1st.spec.ts`
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```
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it('null is not the same thing as undefined',
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() => expect(null).not.toEqual(undefined)
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);
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```
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You knew that right? Let’s prove it with this test. The browser should refresh after you paste that test, and show:
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figure.image-display
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img(src='/resources/images/devguide/jasmine-testing-101/test-report-2-specs-0-failures.png' style="height:100px;" alt="refreshed 2 specs, 0 failures")
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:markdown
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What does a failing test look like? Remove the `.not`. The browser refreshes and shows:
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figure.image-display
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img(src='/resources/images/devguide/jasmine-testing-101/test-report-2-specs-1-failure.png' style="height:190px;" alt="failing test 2 specs, 1 failure")
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:markdown
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Click the `Spec List` link just below “2 specs, 1 failure” to see the summary again:
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figure.image-display
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img(src='/resources/images/devguide/jasmine-testing-101/spec-list-2-specs-1-failure.png' style="height:140px;" alt="2 specs, 1 failure")
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:markdown
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We can re-run just the failing test by double-clicking it. Try it!
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.l-main-section
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:markdown
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## Debug the test
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Suppose we didn’t know what was going on. We can debug it in the browser.
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- Open the browser’s “Developer Tools” (F12 or Ctrl-Shift-I).
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- Pick the “sources” section
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- Open the `1st.spec.ts` test file (Ctrl-P, then start typing the name of the file).
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- Set a breakpoint on the second line of the failing test
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- Refresh the browser … and it stops at our breakpoint.
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- Open the console window at the bottom (press Esc)
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- Type `null === undefined` … … and we should see this:
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figure.image-display
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img(src='/resources/images/devguide/jasmine-testing-101/null-to-equal-undefined.png' style="height:500px;" alt="null === undefined")
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:markdown
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How about that! They really aren’t equal.
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- remove the breakpoint (right-click in the “Breakpoints” section and chose “Remove breakpoint”)
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- Click the “play” icon to resume the test (or F8)
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And the test finishes. Close the browser tools (click the close box or press F12 or Ctrl-Shift-I)
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Fix the test (restore the `.not`); the browser should refresh automatically and all tests pass.
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Congratulations … you’ve completed Jasmine testing 101.
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<!-- TODO
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.l-main-section
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:markdown
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## Learn more
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Learn more about basic Jasmine testing here
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[Resources TBD](./#)
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-->
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.l-main-section
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:markdown
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## What’s Next?
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Now that we’re familiar with Jasmine on its own, we’re ready to test an application.
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What application? We introduce you to it in the next chapter. |