[dartdoc_test] add documentation samples analyzer

[takumma]

• including suggestions from review of [dartdoc_test] add extractor tests and wrap code with imports #241
  • add License headers to all files.
  • add LF/CRLF line breaks tests.
  • add documentation comments.
• implement analysis.

[jonasfj]

nit: Consider writing it on the same form as the actualText that way it becomes super easy to compare what charaters changed.

Suggested change

	final expectText = '''
	This is a linux line break comment.
	```dart
	final x = 1;
	```''';
	final expectText = '''This is a linux line break comment.\n```dart\nfinal x = 1;\n```''';

[takumma]

I fixed it so. thank you :)

[jonasfj]

I'd avoid making stateful global variables like currentContext, testDirectory, resourceProvider.

Consider making a DartDocTestContext and placing all the state you need on that. Or something like that. Could also be called a TestContext just to keep name short and simple :D

[takumma]

I created a singleton class called TestContext.

[chinmoy12c]

I'm not sure I understand this README. Can we have a proper README explaining, how to setup and test things?

[takumma]

It is a example app's README, but I made it better :)

[jonasfj]

I'd suggest not using global activate.

Instead, I'd suggest user do:

# Add dartdoc_test as a dev-dependency
dart pub add dev:dartdoc_test

# Run dartdoc_test directly
dart run dartdoc_test     # This will run bin/dartdoc_test.dart from package:dartdoc_test in your dependencies.

# Add a file to your own tests
cat << EOF > test/dartdoc_test.dart
import 'package:dartdoc_test:dartdoc_test.dart';
import 'package:test/test.dart';
void main() {
  test('analyze documentation code samples' {
    DartDocTest().analyze();
  });
}
EOF

# Now you can run tests with
dart test

We could also make:

# add dartdoc_test as a dev-depenedency
dart pub add dev:dartdoc_test

# run dartdoc test
dart run dartdoc_test

# Add a file in test/dartdoc_test.dart
dart run dartdoc_test add

[jonasfj]

nit

Suggested change

	void main() {
	void main() => runDartdocTest();