To improve cross platform support, all file access (and path manipulation)
is now done through a well known interface (`FileSystem`).
For testing a number of `MockFileSystem` implementations are provided.
These provide an in-memory file-system which emulates operating systems
like OS/X, Unix and Windows.
The current file system is always available via the static method,
`FileSystem.getFileSystem()`. This is also used by a number of static
methods on `AbsoluteFsPath` and `PathSegment`, to avoid having to pass
`FileSystem` objects around all the time. The result of this is that one
must be careful to ensure that the file-system has been initialized before
using any of these static methods. To prevent this happening accidentally
the current file system always starts out as an instance of `InvalidFileSystem`,
which will throw an error if any of its methods are called.
You can set the current file-system by calling `FileSystem.setFileSystem()`.
During testing you can call the helper function `initMockFileSystem(os)`
which takes a string name of the OS to emulate, and will also monkey-patch
aspects of the TypeScript library to ensure that TS is also using the
current file-system.
Finally there is the `NgtscCompilerHost` to be used for any TypeScript
compilation, which uses a given file-system.
All tests that interact with the file-system should be tested against each
of the mock file-systems. A series of helpers have been provided to support
such tests:
* `runInEachFileSystem()` - wrap your tests in this helper to run all the
wrapped tests in each of the mock file-systems.
* `addTestFilesToFileSystem()` - use this to add files and their contents
to the mock file system for testing.
* `loadTestFilesFromDisk()` - use this to load a mirror image of files on
disk into the in-memory mock file-system.
* `loadFakeCore()` - use this to load a fake version of `@angular/core`
into the mock file-system.
All ngcc and ngtsc source and tests now use this virtual file-system setup.
PR Close#30921
Currently the `@angular/compiler-cli` compliance tests sometimes do
not throw an exception if the expected output does not match the
generated JavaScript output. This can happen for the following cases:
1. Expected code includes character that is not part of known alphabet
(e.g. `Δ` is still used in a new compliance test after rebasing a PR)
2. Expected code asserts that a string literal matches a string with
escaped quotes. e.g. expects `const $var$ = "\"quoted\"";`)
PR Close#30597
There is an encoding issue with using delta `Δ`, where the browser will attempt to detect the file encoding if the character set is not explicitly declared on a `<script/>` tag, and Chrome will find the `Δ` character and decide it is window-1252 encoding, which misinterprets the `Δ` character to be some other character that is not a valid JS identifier character
So back to the frog eyes we go.
```
__
/ɵɵ\
( -- ) - I am ineffable. I am forever.
_/ \_
/ \ / \
== == ==
```
PR Close#30546
before:
```
Expected to find features 'import * as i0 from "@angular/core";
import { Directive, Input } from '@angular/core';
```
after:
```
Failed to find "template" after "...Component_Factory() { return new
MyComponent(); }," in:
'import * as i0 from "@angular/core";
import { Directive, Input } from '@angular/core';```
```
PR Close#25291
This commit moves the compiler compliance tests into compiler-cli,
and uses ngtsc to run them instead of the custom compilation
pipeline used before. Testing against ngtsc allows for validation
of the real compiler output.
This commit also fixes a few small issues that prevented the tests
from passing.
PR Close#24862
Pete Bacon Darwin
Paul Gschwendtner
Ben Lesh
Kara Erickson
Victor Berchet
Alex Rickabaugh