[flutter_tools] Add channel order aware version_test (#62417)

packages/flutter_tools/lib/src/commands/channel.dart

@@ -72,7 +72,7 @@ class ChannelCommand extends FlutterCommand {
       throwToolExit('List channels failed: $result$details', exitCode: result);
     }
 
-    final List<String> officialChannels = FlutterVersion.officialChannels.toList();
+    final List<String> officialChannels = kOfficialChannels.toList();
     final List<bool> availableChannels = List<bool>.filled(officialChannels.length, false);
 
     for (final String line in rawOutput) {
@@ -116,10 +116,10 @@ class ChannelCommand extends FlutterCommand {
 
   Future<void> _switchChannel(String branchName) async {
     globals.printStatus("Switching to flutter channel '$branchName'...");
-    if (FlutterVersion.obsoleteBranches.containsKey(branchName)) {
-      final String alternative = FlutterVersion.obsoleteBranches[branchName];
+    if (kObsoleteBranches.containsKey(branchName)) {
+      final String alternative = kObsoleteBranches[branchName];
       globals.printStatus("This channel is obsolete. Consider switching to the '$alternative' channel instead.");
-    } else if (!FlutterVersion.officialChannels.contains(branchName)) {
+    } else if (!kOfficialChannels.contains(branchName)) {
       globals.printStatus('This is not an official channel. For a list of available channels, try "flutter channel".');
     }
     await _checkout(branchName);
@@ -129,8 +129,8 @@ class ChannelCommand extends FlutterCommand {
 
   static Future<void> upgradeChannel() async {
     final String channel = globals.flutterVersion.channel;
-    if (FlutterVersion.obsoleteBranches.containsKey(channel)) {
-      final String alternative = FlutterVersion.obsoleteBranches[channel];
+    if (kObsoleteBranches.containsKey(channel)) {
+      final String alternative = kObsoleteBranches[channel];
       globals.printStatus("Transitioning from '$channel' to '$alternative'...");
       return _checkout(alternative);
     }

packages/flutter_tools/lib/src/commands/upgrade.dart

@@ -107,7 +107,7 @@ class UpgradeCommandRunner {
     if (!force && gitTagVersion == const GitTagVersion.unknown()) {
       // If the commit is a recognized branch and not master,
       // explain that we are avoiding potential damage.
-      if (flutterVersion.channel != 'master' && FlutterVersion.officialChannels.contains(flutterVersion.channel)) {
+      if (flutterVersion.channel != 'master' && kOfficialChannels.contains(flutterVersion.channel)) {
         throwToolExit(
           'Unknown flutter tag. Abandoning upgrade to avoid destroying local '
           'changes. It is recommended to use git directly if not working on '

packages/flutter_tools/lib/src/version.dart

@@ -13,6 +13,20 @@ import 'cache.dart';
 import 'convert.dart';
 import 'globals.dart' as globals;
 
+/// The flutter GitHub repository.
+String get _flutterGit => globals.platform.environment['FLUTTER_GIT_URL'] ?? 'https://github.com/flutter/flutter.git';
+
+/// This maps old branch names to the names of branches that replaced them.
+///
+/// For example, in early 2018 we changed from having an "alpha" branch to
+/// having a "dev" branch, so anyone using "alpha" now gets transitioned to
+/// "dev".
+const Map<String, String> kObsoleteBranches = <String, String>{
+  'alpha': 'dev',
+  'hackathon': 'dev',
+  'codelab': 'dev',
+};
+
 /// The names of each channel/branch in order of increasing stability.
 enum Channel {
   master,
@@ -21,23 +35,28 @@ enum Channel {
   stable,
 }
 
-/// The flutter GitHub repository.
-String get _flutterGit => globals.platform.environment['FLUTTER_GIT_URL'] ?? 'https://github.com/flutter/flutter.git';
+// Beware: Keep order in accordance with stability
+const Set<String> kOfficialChannels = <String>{
+  'master',
+  'dev',
+  'beta',
+  'stable',
+};
 
 /// Retrieve a human-readable name for a given [channel].
 ///
-/// Requires [FlutterVersion.officialChannels] to be correctly ordered.
+/// Requires [kOfficialChannels] to be correctly ordered.
 String getNameForChannel(Channel channel) {
-  return FlutterVersion.officialChannels.elementAt(channel.index);
+  return kOfficialChannels.elementAt(channel.index);
 }
 
 /// Retrieve the [Channel] representation for a string [name].
 ///
 /// Returns `null` if [name] is not in the list of official channels, according
-/// to [FlutterVersion.officialChannels].
+/// to [kOfficialChannels].
 Channel getChannelForName(String name) {
-  if (FlutterVersion.officialChannels.contains(name)) {
-    return Channel.values[FlutterVersion.officialChannels.toList().indexOf(name)];
+  if (kOfficialChannels.contains(name)) {
+    return Channel.values[kOfficialChannels.toList().indexOf(name)];
   }
   return null;
 }
@@ -84,25 +103,6 @@ class FlutterVersion {
     return !<String>['dev', 'beta', 'stable'].contains(branchName);
   }
 
-  // Beware: Keep order in accordance with stability
-  static const Set<String> officialChannels = <String>{
-    'master',
-    'dev',
-    'beta',
-    'stable',
-  };
-
-  /// This maps old branch names to the names of branches that replaced them.
-  ///
-  /// For example, in early 2018 we changed from having an "alpha" branch to
-  /// having a "dev" branch, so anyone using "alpha" now gets transitioned to
-  /// "dev".
-  static Map<String, String> obsoleteBranches = <String, String>{
-    'alpha': 'dev',
-    'hackathon': 'dev',
-    'codelab': 'dev',
-  };
-
   String _channel;
   /// The channel is the upstream branch.
   /// `master`, `dev`, `beta`, `stable`; or old ones, like `alpha`, `hackathon`, ...
@@ -298,8 +298,8 @@ class FlutterVersion {
     }();
     if (redactUnknownBranches || _branch.isEmpty) {
       // Only return the branch names we know about; arbitrary branch names might contain PII.
-      if (!officialChannels.contains(_branch) &&
-          !obsoleteBranches.containsKey(_branch)) {
+      if (!kOfficialChannels.contains(_branch) &&
+          !kObsoleteBranches.containsKey(_branch)) {
         return '[user-branch]';
       }
     }
@@ -388,7 +388,7 @@ class FlutterVersion {
   /// writes shared cache files.
   Future<void> checkFlutterVersionFreshness() async {
     // Don't perform update checks if we're not on an official channel.
-    if (!officialChannels.contains(channel)) {
+    if (!kOfficialChannels.contains(channel)) {
       return;
     }
 

packages/flutter_tools/test/general.shard/channel_test.dart

@@ -86,7 +86,7 @@ void main() {
       final Iterable<String> rows = testLogger.statusText
         .split('\n')
         .map((String line) => line.substring(2)); // remove '* ' or '  ' from output
-      expect(rows, containsAllInOrder(FlutterVersion.officialChannels));
+      expect(rows, containsAllInOrder(kOfficialChannels));
 
       // clear buffer for next process
       testLogger.clear();
@@ -107,7 +107,7 @@ void main() {
       final Iterable<String> rows2 = testLogger.statusText
         .split('\n')
         .map((String line) => line.substring(2)); // remove '* ' or '  ' from output
-      expect(rows2, containsAllInOrder(FlutterVersion.officialChannels));
+      expect(rows2, containsAllInOrder(kOfficialChannels));
 
       // clear buffer for next process
       testLogger.clear();
@@ -127,7 +127,7 @@ void main() {
       // check if available official channels are in order of stability
       int prev = -1;
       int next = -1;
-      for (final String branch in FlutterVersion.officialChannels) {
+      for (final String branch in kOfficialChannels) {
         next = testLogger.statusText.indexOf(branch);
         if (next != -1) {
           expect(prev < next, isTrue);

packages/flutter_tools/test/general.shard/version_test.dart

@@ -36,7 +36,15 @@ void main() {
     mockCache = MockCache();
   });
 
-  for (final String channel in FlutterVersion.officialChannels) {
+  testUsingContext('Channel enum and string transform to each other', () {
+    for (final Channel channel in Channel.values) {
+      expect(getNameForChannel(channel), kOfficialChannels.toList()[channel.index]);
+    }
+    expect(kOfficialChannels.toList().map((String str) => getChannelForName(str)).toList(),
+      Channel.values);
+  });
+
+  for (final String channel in kOfficialChannels) {
     DateTime getChannelUpToDateVersion() {
       return _testClock.ago(FlutterVersion.versionAgeConsideredUpToDate(channel) ~/ 2);
     }