Minor cleanup in json_reporter_utils (#2039)

- Decode the output once instead of repeatedly decoding it for every
  `expect` call.
- Use `=>` for single expression return methods.
- Use conditional collection elements where applicable.

pkgs/test/test/runner/json_reporter_utils.dart

@@ -24,12 +24,15 @@ Future<void> expectJsonReport(
  expect(outputLines,
  hasLength(expected.fold<int>(3, (int a, m) => a + m.length)));
 
- dynamic decodeLine(String l) => jsonDecode(l)
- ..remove('time')
- ..remove('stackTrace');
+ final decoded = [
+ for (final line in outputLines)
+ (jsonDecode(line) as Map)
+ ..remove('time')
+ ..remove('stackTrace')
+ ];
 
  // Should contain all suites message.
- expect(outputLines.map(decodeLine), containsAll([allSuitesJson()]));
+ expect(decoded, containsAll([_allSuitesJson()]));
 
  // A single start event is emitted first.
  final start = {
@@ -38,39 +41,37 @@ Future<void> expectJsonReport(
  'runnerVersion': testVersion,
  'pid': testPid,
  };
- expect(decodeLine(outputLines.first), equals(start));
+ expect(decoded.first, equals(start));
 
  // A single done event is emitted last.
- expect(decodeLine(outputLines.last), equals(done));
+ expect(decoded.last, equals(done));
 
  for (var value in expected) {
- expect(outputLines.map(decodeLine), containsAllInOrder(value));
+ expect(decoded, containsAllInOrder(value));
  }
 }
 
 /// Returns the event emitted by the JSON reporter providing information about
 /// all suites.
 ///
 /// The [count] defaults to 1.
-Map<String, Object> allSuitesJson({int count = 1}) {
- return {'type': 'allSuites', 'count': count};
-}
+Map<String, Object> _allSuitesJson({int count = 1}) =>
+ {'type': 'allSuites', 'count': count};
 
 /// Returns the event emitted by the JSON reporter indicating that a suite has
 /// begun running.
 ///
 /// The [platform] defaults to `"vm"`, the [path] defaults to `"test.dart"`.
 Map<String, Object> suiteJson(int id,
- {String platform = 'vm', String path = 'test.dart'}) {
- return {
- 'type': 'suite',
- 'suite': {
- 'id': id,
- 'platform': platform,
- 'path': path,
- }
- };
-}
+ {String platform = 'vm', String path = 'test.dart'}) =>
+ {
+ 'type': 'suite',
+ 'suite': {
+ 'id': id,
+ 'platform': platform,
+ 'path': path,
+ }
+ };
 
 /// Returns the event emitted by the JSON reporter indicating that a group has
 /// begun running.
@@ -101,7 +102,7 @@ Map<String, Object> groupJson(int id,
  'name': name ?? '',
  'suiteID': suiteID ?? 0,
  'parentID': parentID,
- 'metadata': metadataJson(skip: skip),
+ 'metadata': _metadataJson(skip: skip),
  'testCount': testCount ?? 1,
  'line': line,
  'column': column,
@@ -136,58 +137,43 @@ Map<String, Object> testStartJson(int id, String name,
 
  url ??=
  line == null ? null : p.toUri(p.join(d.sandbox, 'test.dart')).toString();
- var expected = {
+ return {
  'type': 'testStart',
  'test': {
  'id': id,
  'name': name,
  'suiteID': suiteID ?? 0,
  'groupIDs': groupIDs ?? [2],
- 'metadata': metadataJson(skip: skip),
+ 'metadata': _metadataJson(skip: skip),
  'line': line,
  'column': column,
  'url': url,
+ if (rootLine != null) 'root_line': rootLine,
+ if (rootColumn != null) 'root_column': rootColumn,
+ if (rootUrl != null) 'root_url': rootUrl,
  }
  };
- var testObj = expected['test'] as Map<String, dynamic>;
- if (rootLine != null) {
- testObj['root_line'] = rootLine;
- }
- if (rootColumn != null) {
- testObj['root_column'] = rootColumn;
- }
- if (rootUrl != null) {
- testObj['root_url'] = rootUrl;
- }
- return expected;
 }
 
 /// Returns the event emitted by the JSON reporter indicating that a test
 /// printed [message].
 Matcher printJson(int id, dynamic /*String|Matcher*/ message,
- {String type = 'print'}) {
- return allOf(
- hasLength(4),
- containsPair('type', 'print'),
- containsPair('testID', id),
- containsPair('message', message),
- containsPair('messageType', type),
- );
-}
+ {String type = 'print'}) =>
+ allOf(
+ hasLength(4),
+ containsPair('type', 'print'),
+ containsPair('testID', id),
+ containsPair('message', message),
+ containsPair('messageType', type),
+ );
 
 /// Returns the event emitted by the JSON reporter indicating that a test
 /// emitted [error].
 ///
 /// The [isFailure] parameter indicates whether the error was a [TestFailure] or
 /// not.
-Map<String, Object> errorJson(int id, String error, {bool isFailure = false}) {
- return {
- 'type': 'error',
- 'testID': id,
- 'error': error,
- 'isFailure': isFailure
- };
-}
+Map<String, Object> errorJson(int id, String error, {bool isFailure = false}) =>
+ {'type': 'error', 'testID': id, 'error': error, 'isFailure': isFailure};
 
 /// Returns the event emitted by the JSON reporter indicating that a test
 /// finished.
@@ -199,28 +185,24 @@ Map<String, Object> errorJson(int id, String error, {bool isFailure = false}) {
 /// after finishing. The [skipped] parameter indicates whether the test was
 /// skipped.
 Map<String, Object> testDoneJson(int id,
- {String result = 'success', bool hidden = false, bool skipped = false}) {
- return {
- 'type': 'testDone',
- 'testID': id,
- 'result': result,
- 'hidden': hidden,
- 'skipped': skipped
- };
-}
+ {String result = 'success',
+ bool hidden = false,
+ bool skipped = false}) =>
+ {
+ 'type': 'testDone',
+ 'testID': id,
+ 'result': result,
+ 'hidden': hidden,
+ 'skipped': skipped
+ };
 
 /// Returns the event emitted by the JSON reporter indicating that the entire
 /// run finished.
 Map<String, Object> doneJson({bool success = true}) =>
  {'type': 'done', 'success': success};
 
 /// Returns the serialized metadata corresponding to [skip].
-Map<String, Object?> metadataJson({Object? skip}) {
- if (skip == true) {
- return {'skip': true, 'skipReason': null};
- } else if (skip is String) {
- return {'skip': true, 'skipReason': skip};
- } else {
- return {'skip': false, 'skipReason': null};
- }
-}
+Map<String, Object?> _metadataJson({Object? skip}) => {
+ 'skip': skip == true || skip is String,
+ 'skipReason': skip is String ? skip : null
+ };