In many testing scenarios, there is a common pattern:
1. Overwrite template (inline or external)
2. Find cursor position
3. Call one of language service APIs
4. Inspect spans in result
In order to faciliate this pattern, this commit refactors
`MockHost.overwrite()` and `MockHost.overwriteInlineTemplate()` to
allow a faux cursor symbol `¦` to be injected into the template, and
the methods will automatically remove it before updating the script snapshot.
Both methods will return the cursor position and the new text without
the cursor symbol.
This makes testing very convenient. Here's a typical example:
```ts
const {position, text} = mockHost.overwrite('template.html', `{{ ti¦tle }}`);
const quickInfo = ngLS.getQuickInfoAtPosition('template.html', position);
const {start, length} = quickInfo!.textSpan;
expect(text.substring(start, start + length)).toBe('title');
```
PR Close#38552
This commit adds a Compiler interface that wraps the actual ngtsc
compiler. The language-service specific compiler manages multiple
typecheck files using the Project interface, creating and adding
ScriptInfos as necessary.
This commit also adds `overrideInlineTemplate()` method to the mock
service so that we could test the Compiler diagnostics feature.
PR Close#36930
Keen Yee Liau
Joey Perrott
Keen Yee Liau