2020-06-30 18:14:34 +00:00
# Testing Pipes
docs: Migrate pipe guide and its code examples to standalone (#51333)
**Pipes Sample Code**
Migrated all sample code in the `examples/pipes` folder. Did not touch the pipes in the ToH or Testing folders.
>The existing, complex discussion of the `CurrencyPipe` within `pipes-transform-data.md` cried out for a new `concurrency-formatting.component` example`.
**Extracted "pipe precedence" into its own page**
The topic had been extracted from `pipe.md` and tacked on to the bottom of the `pipes-overview.md` page.
It's an advanced and somewhat obscure topic that doesn't belong in the overview. Rather than throw it away, I created a new `pipe-precedence.md` page and added it to the bottom of the pipes section navigation.
I also tried to improve both the guide text and the companion component, `precedence.component`.
**How to create a pipe is missing**
The readers are told they can create their own pipes in several places throughout the docs. But there are no links and you can't navigate to a page that covers the topic. This is a serious omission!
The topic is introduced in the `pipes-custom-data-trans.md` page (extracted verbatim from `pipes.md`). But you can't navigate to this page and their are no links to it.
TODO: restore this page and add it to the left-nav.
**Change `pipes.md` references to `pipe-overview.md`**
The original, kitchen-sink page, `pipes.md`, was disconnected from navigation long ago, in favor of multiple pages such as `pipe-overview.md`. The page is still in the AIO documentation and can be found by searching or by links from 3rd party documenters. Landing on that page hides the left-nav.
In this commit, we treat `pipes.md` as deprecated (which it seems to be). Therefore, this commit retargets previous `pipes.md` references to `pipe-overview.md`.
>The `change-detection-slow-computations.md` is the exception. It refers to "pure pipes", a subject not covered in the current pipe documentation. That reference is retargeted to `api/core/Pipe#pure`.
Certain code files are only referenced in `pipe.md`. They still work and are displayed in the overall pipes code sample as before. Now they are marked with deprecation comments for future treatment or removal.
For consistency, certain sections of `pipes.md` were replaced by the contents of the corresponding current pages.
PR Close #51333
2023-08-10 06:34:27 +00:00
You can test [pipes ](guide/pipes-overview ) without the Angular testing utilities.
2020-06-30 18:14:34 +00:00
< div class = "alert is-helpful" >
docs: improve markdown (#45325)
The purpose of the changes is to clean all markdown to match a single pedantic style.
* To ensure all changes in style are properly separated.
* To ensure all styled content aligns to nearest 4-character-tab.
* To ensure all code blocks use the Angular `<code-example>` or `<code-tab>` elements.
* To ensure all markdown exists outside of html tags.
* To ensure all images use the Angular style for `<img>` elements.
* To ensure that all smart punctuation is replaced or removed.
```text
’, ’, “, ”, –, —, …
```
* To ensure all content does not conflict with the following reserved characters.
```text
@, $, *, &, #, |, <, >,
```
* To ensure all content displays using html entities.
The following changes were made to files in the following directory.
```text
aio/content
```
The target files were markdown files.
The list of excluded files:
```text
.browserslistrc, .css, .conf, .editorconfig, .gitignore, .html, .js, .json, .sh, .svg, .ts, .txt, .xlf,
```
PR Close #45325
2022-03-10 16:48:09 +00:00
If you'd like to experiment with the application that this guide describes, < live-example name = "testing" noDownload > run it in your browser< / live-example > or < live-example name = "testing" downloadOnly > download and run it locally< / live-example > .
2020-06-30 18:14:34 +00:00
< / div >
## Testing the `TitleCasePipe`
docs: improve markdown (#45325)
The purpose of the changes is to clean all markdown to match a single pedantic style.
* To ensure all changes in style are properly separated.
* To ensure all styled content aligns to nearest 4-character-tab.
* To ensure all code blocks use the Angular `<code-example>` or `<code-tab>` elements.
* To ensure all markdown exists outside of html tags.
* To ensure all images use the Angular style for `<img>` elements.
* To ensure that all smart punctuation is replaced or removed.
```text
’, ’, “, ”, –, —, …
```
* To ensure all content does not conflict with the following reserved characters.
```text
@, $, *, &, #, |, <, >,
```
* To ensure all content displays using html entities.
The following changes were made to files in the following directory.
```text
aio/content
```
The target files were markdown files.
The list of excluded files:
```text
.browserslistrc, .css, .conf, .editorconfig, .gitignore, .html, .js, .json, .sh, .svg, .ts, .txt, .xlf,
```
PR Close #45325
2022-03-10 16:48:09 +00:00
A pipe class has one method, `transform` , that manipulates the input value into a transformed output value.
2020-06-30 18:14:34 +00:00
The `transform` implementation rarely interacts with the DOM.
docs: improve markdown (#45325)
The purpose of the changes is to clean all markdown to match a single pedantic style.
* To ensure all changes in style are properly separated.
* To ensure all styled content aligns to nearest 4-character-tab.
* To ensure all code blocks use the Angular `<code-example>` or `<code-tab>` elements.
* To ensure all markdown exists outside of html tags.
* To ensure all images use the Angular style for `<img>` elements.
* To ensure that all smart punctuation is replaced or removed.
```text
’, ’, “, ”, –, —, …
```
* To ensure all content does not conflict with the following reserved characters.
```text
@, $, *, &, #, |, <, >,
```
* To ensure all content displays using html entities.
The following changes were made to files in the following directory.
```text
aio/content
```
The target files were markdown files.
The list of excluded files:
```text
.browserslistrc, .css, .conf, .editorconfig, .gitignore, .html, .js, .json, .sh, .svg, .ts, .txt, .xlf,
```
PR Close #45325
2022-03-10 16:48:09 +00:00
Most pipes have no dependence on Angular other than the `@Pipe` metadata and an interface.
2020-06-30 18:14:34 +00:00
Consider a `TitleCasePipe` that capitalizes the first letter of each word.
Here's an implementation with a regular expression.
docs: improve markdown (#45325)
The purpose of the changes is to clean all markdown to match a single pedantic style.
* To ensure all changes in style are properly separated.
* To ensure all styled content aligns to nearest 4-character-tab.
* To ensure all code blocks use the Angular `<code-example>` or `<code-tab>` elements.
* To ensure all markdown exists outside of html tags.
* To ensure all images use the Angular style for `<img>` elements.
* To ensure that all smart punctuation is replaced or removed.
```text
’, ’, “, ”, –, —, …
```
* To ensure all content does not conflict with the following reserved characters.
```text
@, $, *, &, #, |, <, >,
```
* To ensure all content displays using html entities.
The following changes were made to files in the following directory.
```text
aio/content
```
The target files were markdown files.
The list of excluded files:
```text
.browserslistrc, .css, .conf, .editorconfig, .gitignore, .html, .js, .json, .sh, .svg, .ts, .txt, .xlf,
```
PR Close #45325
2022-03-10 16:48:09 +00:00
< code-example header = "app/shared/title-case.pipe.ts" path = "testing/src/app/shared/title-case.pipe.ts" > < / code-example >
2020-06-30 18:14:34 +00:00
Anything that uses a regular expression is worth testing thoroughly.
Use simple Jasmine to explore the expected cases and the edge cases.
docs: improve markdown (#45325)
The purpose of the changes is to clean all markdown to match a single pedantic style.
* To ensure all changes in style are properly separated.
* To ensure all styled content aligns to nearest 4-character-tab.
* To ensure all code blocks use the Angular `<code-example>` or `<code-tab>` elements.
* To ensure all markdown exists outside of html tags.
* To ensure all images use the Angular style for `<img>` elements.
* To ensure that all smart punctuation is replaced or removed.
```text
’, ’, “, ”, –, —, …
```
* To ensure all content does not conflict with the following reserved characters.
```text
@, $, *, &, #, |, <, >,
```
* To ensure all content displays using html entities.
The following changes were made to files in the following directory.
```text
aio/content
```
The target files were markdown files.
The list of excluded files:
```text
.browserslistrc, .css, .conf, .editorconfig, .gitignore, .html, .js, .json, .sh, .svg, .ts, .txt, .xlf,
```
PR Close #45325
2022-03-10 16:48:09 +00:00
< code-example header = "app/shared/title-case.pipe.spec.ts" path = "testing/src/app/shared/title-case.pipe.spec.ts" region = "excerpt" > < / code-example >
2020-06-30 18:14:34 +00:00
docs: improve markdown (#45325)
The purpose of the changes is to clean all markdown to match a single pedantic style.
* To ensure all changes in style are properly separated.
* To ensure all styled content aligns to nearest 4-character-tab.
* To ensure all code blocks use the Angular `<code-example>` or `<code-tab>` elements.
* To ensure all markdown exists outside of html tags.
* To ensure all images use the Angular style for `<img>` elements.
* To ensure that all smart punctuation is replaced or removed.
```text
’, ’, “, ”, –, —, …
```
* To ensure all content does not conflict with the following reserved characters.
```text
@, $, *, &, #, |, <, >,
```
* To ensure all content displays using html entities.
The following changes were made to files in the following directory.
```text
aio/content
```
The target files were markdown files.
The list of excluded files:
```text
.browserslistrc, .css, .conf, .editorconfig, .gitignore, .html, .js, .json, .sh, .svg, .ts, .txt, .xlf,
```
PR Close #45325
2022-03-10 16:48:09 +00:00
< a id = "write-tests" > < / a >
2020-06-30 18:14:34 +00:00
## Writing DOM tests to support a pipe test
docs: improve markdown (#45325)
The purpose of the changes is to clean all markdown to match a single pedantic style.
* To ensure all changes in style are properly separated.
* To ensure all styled content aligns to nearest 4-character-tab.
* To ensure all code blocks use the Angular `<code-example>` or `<code-tab>` elements.
* To ensure all markdown exists outside of html tags.
* To ensure all images use the Angular style for `<img>` elements.
* To ensure that all smart punctuation is replaced or removed.
```text
’, ’, “, ”, –, —, …
```
* To ensure all content does not conflict with the following reserved characters.
```text
@, $, *, &, #, |, <, >,
```
* To ensure all content displays using html entities.
The following changes were made to files in the following directory.
```text
aio/content
```
The target files were markdown files.
The list of excluded files:
```text
.browserslistrc, .css, .conf, .editorconfig, .gitignore, .html, .js, .json, .sh, .svg, .ts, .txt, .xlf,
```
PR Close #45325
2022-03-10 16:48:09 +00:00
These are tests of the pipe *in isolation* .
2020-06-30 18:14:34 +00:00
They can't tell if the `TitleCasePipe` is working properly as applied in the application components.
Consider adding component tests such as this one:
docs: improve markdown (#45325)
The purpose of the changes is to clean all markdown to match a single pedantic style.
* To ensure all changes in style are properly separated.
* To ensure all styled content aligns to nearest 4-character-tab.
* To ensure all code blocks use the Angular `<code-example>` or `<code-tab>` elements.
* To ensure all markdown exists outside of html tags.
* To ensure all images use the Angular style for `<img>` elements.
* To ensure that all smart punctuation is replaced or removed.
```text
’, ’, “, ”, –, —, …
```
* To ensure all content does not conflict with the following reserved characters.
```text
@, $, *, &, #, |, <, >,
```
* To ensure all content displays using html entities.
The following changes were made to files in the following directory.
```text
aio/content
```
The target files were markdown files.
The list of excluded files:
```text
.browserslistrc, .css, .conf, .editorconfig, .gitignore, .html, .js, .json, .sh, .svg, .ts, .txt, .xlf,
```
PR Close #45325
2022-03-10 16:48:09 +00:00
< code-example header = "app/hero/hero-detail.component.spec.ts (pipe test)" path = "testing/src/app/hero/hero-detail.component.spec.ts" region = "title-case-pipe" > < / code-example >
2020-06-30 18:14:34 +00:00
docs: improve markdown (#45325)
The purpose of the changes is to clean all markdown to match a single pedantic style.
* To ensure all changes in style are properly separated.
* To ensure all styled content aligns to nearest 4-character-tab.
* To ensure all code blocks use the Angular `<code-example>` or `<code-tab>` elements.
* To ensure all markdown exists outside of html tags.
* To ensure all images use the Angular style for `<img>` elements.
* To ensure that all smart punctuation is replaced or removed.
```text
’, ’, “, ”, –, —, …
```
* To ensure all content does not conflict with the following reserved characters.
```text
@, $, *, &, #, |, <, >,
```
* To ensure all content displays using html entities.
The following changes were made to files in the following directory.
```text
aio/content
```
The target files were markdown files.
The list of excluded files:
```text
.browserslistrc, .css, .conf, .editorconfig, .gitignore, .html, .js, .json, .sh, .svg, .ts, .txt, .xlf,
```
PR Close #45325
2022-03-10 16:48:09 +00:00
<!-- links -->
<!-- external links -->
<!-- end links -->
2023-09-12 18:25:40 +00:00
@reviewed 2023-09-07
