Add test to compare-failures

tools/gardening/bin/compare_failures.dart

Index: tools/gardening/bin/compare_failures.dart
diff --git a/tools/gardening/bin/compare_failures.dart b/tools/gardening/bin/compare_failures.dart
index de888914be7afeb83cc238627fb96899dad3d456..67f39db33493887731faaf9f30af4b6d4ccc01a6 100644
--- a/tools/gardening/bin/compare_failures.dart
+++ b/tools/gardening/bin/compare_failures.dart
@@ -6,12 +6,11 @@
 ///
 /// Use this to detect flakiness of failures, especially timeouts.
 
-import 'dart:async';
 import 'dart:io';
 
 import 'package:args/args.dart';
-import 'package:gardening/src/buildbot_structures.dart';
 import 'package:gardening/src/client.dart';
+import 'package:gardening/src/compare_failures_impl.dart';
 import 'package:gardening/src/util.dart';
 
 void help(ArgParser argParser) {
@@ -19,9 +18,11 @@ void help(ArgParser argParser) {
   print('fetches earlier runs of the same bot and compares the results.');
   print('This tool is particularly useful to detect flakes and their ');
   print('frequency.');
-  print('Usage: compare_failures [options] <log-uri>');
-  print('where <log-uri> is the uri the stdio output of a failing test step');
-  print('and options are:');
+  print('Usage: compare_failures [options] ');
+  print('  (<log-uri> [<log-uri> ...] | <build-group> [<build-group> ...])');
+  print('where <log-uri> is the uri the stdio output of a failing test step ');
+  print('and <build-group> is the name of a buildbot group, for instance ');
+  print('`vm-kernel`, and options are:');
   print(argParser.usage);
 }
 
@@ -32,10 +33,6 @@ main(List<String> args) async {
   ArgResults argResults = argParser.parse(args);
   processArgResults(argResults);
 
-  BuildbotClient client = argResults['logdog']
-      ? new LogdogBuildbotClient()
-      : new HttpBuildbotClient();
-
   var runCount = int.parse(argResults['run-count'], onError: (_) => null);
 
   if (argResults.rest.length != 1 || argResults['help'] || runCount == null) {
@@ -43,116 +40,10 @@ main(List<String> args) async {
     if (argResults['help']) return;
     exit(1);
   }
-  String url = argResults.rest.first;
-  if (!url.endsWith('/text')) {
-    // Use the text version of the stdio log.
-    url += '/text';
-  }
-  Uri uri = Uri.parse(url);
-  BuildUri buildUri = new BuildUri(uri);
-  List<BuildResult> results =
-      await readBuildResults(client, buildUri, runCount);
-  print(generateBuildResultsSummary(buildUri, results));
-  client.close();
-}
-
-/// Creates a [BuildResult] for [buildUri] and, if it contains failures, the
-/// [BuildResult]s for the previous [runCount] builds.
-Future<List<BuildResult>> readBuildResults(
-    BuildbotClient client, BuildUri buildUri, int runCount) async {
-  List<BuildResult> summaries = <BuildResult>[];
-  BuildResult summary = await client.readResult(buildUri);
-  summaries.add(summary);
-  if (summary.hasFailures) {
-    for (int i = 0; i < runCount; i++) {
-      buildUri = summary.buildUri.prev();
-      summary = await client.readResult(buildUri);
-      summaries.add(summary);
-    }
-  }
-  return summaries;
-}
 
-/// Generate a summary of the timeouts and other failures in [results].
-String generateBuildResultsSummary(
-    BuildUri buildUri, List<BuildResult> results) {
-  StringBuffer sb = new StringBuffer();
-  sb.write('Results for $buildUri:\n');
-  Set<TestConfiguration> timeoutIds = new Set<TestConfiguration>();
-  for (BuildResult result in results) {
-    timeoutIds.addAll(result.timeouts.map((TestFailure failure) => failure.id));
-  }
-  if (timeoutIds.isNotEmpty) {
-    Map<TestConfiguration, Map<int, Map<String, Timing>>> map =
-        <TestConfiguration, Map<int, Map<String, Timing>>>{};
-    Set<String> stepNames = new Set<String>();
-    for (BuildResult result in results) {
-      for (Timing timing in result.timings) {
-        Map<int, Map<String, Timing>> builds =
-            map.putIfAbsent(timing.step.id, () => <int, Map<String, Timing>>{});
-        stepNames.add(timing.step.stepName);
-        builds.putIfAbsent(timing.uri.buildNumber, () => <String, Timing>{})[
-            timing.step.stepName] = timing;
-      }
-    }
-    sb.write('Timeouts for ${buildUri} :\n');
-    map.forEach((TestConfiguration id, Map<int, Map<String, Timing>> timings) {
-      if (!timeoutIds.contains(id)) return;
-      sb.write('$id\n');
-      sb.write(
-          '${' ' * 8} ${stepNames.map((t) => padRight(t, 14)).join(' ')}\n');
-      for (BuildResult result in results) {
-        int buildNumber = result.buildUri.buildNumber;
-        Map<String, Timing> steps = timings[buildNumber] ?? const {};
-        sb.write(padRight(' ${buildNumber}: ', 8));
-        for (String stepName in stepNames) {
-          Timing timing = steps[stepName];
-          if (timing != null) {
-            sb.write(' ${timing.time}');
-          } else {
-            sb.write(' --------------');
-          }
-        }
-        sb.write('\n');
-      }
-      sb.write('\n');
-    });
-  }
-  Set<TestConfiguration> errorIds = new Set<TestConfiguration>();
-  for (BuildResult result in results) {
-    errorIds.addAll(result.errors.map((TestFailure failure) => failure.id));
-  }
-  if (errorIds.isNotEmpty) {
-    Map<TestConfiguration, Map<int, TestFailure>> map =
-        <TestConfiguration, Map<int, TestFailure>>{};
-    for (BuildResult result in results) {
-      for (TestFailure failure in result.errors) {
-        map.putIfAbsent(failure.id, () => <int, TestFailure>{})[
-            failure.uri.buildNumber] = failure;
-      }
-    }
-    sb.write('Errors for ${buildUri} :\n');
-    // TODO(johnniwinther): Improve comparison of non-timeouts.
-    map.forEach((TestConfiguration id, Map<int, TestFailure> failures) {
-      if (!errorIds.contains(id)) return;
-      sb.write('$id\n');
-      for (BuildResult result in results) {
-        int buildNumber = result.buildUri.buildNumber;
-        TestFailure failure = failures[buildNumber];
-        sb.write(padRight(' ${buildNumber}: ', 8));
-        if (failure != null) {
-          sb.write(padRight(failure.expected, 10));
-          sb.write(' / ');
-          sb.write(padRight(failure.actual, 10));
-        } else {
-          sb.write(' ' * 10);
-          sb.write(' / ');
-          sb.write(padRight('-- OK --', 10));
-        }
-        sb.write('\n');
-      }
-      sb.write('\n');
-    });
-  }
-  return sb.toString();
+  BuildbotClient client = argResults['logdog']
+      ? new LogdogBuildbotClient()
+      : new HttpBuildbotClient();
+  await mainInternal(client, argResults.rest, runCount: runCount);
+  client.close();
 }