Switch to backtracking solver.

utils/tests/pub/version_solver_test.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library pub_update_test;
 
 import 'dart:async';
 import 'dart:io';
 
 import 'package:unittest/unittest.dart';
 
 import '../../pub/lock_file.dart';
 import '../../pub/package.dart';
 import '../../pub/pubspec.dart';
 import '../../pub/sdk.dart' as sdk;
 import '../../pub/source.dart';
 import '../../pub/source_registry.dart';
 import '../../pub/system_cache.dart';
 import '../../pub/utils.dart';
 import '../../pub/version.dart';
 import '../../pub/solver/version_solver.dart';
 import 'test_pub.dart';
 
 MockSource source1;
 MockSource source2;
 
-bool allowBacktracking;
-
 main() {
   initConfig();
 
   // Since this test isn't run from the SDK, it can't find the "version" file
   // to load. Instead, just manually inject a version.
   sdk.version = new Version(1, 2, 3);
 
-  for (allowBacktracking in [false, true]) {
-    group(allowBacktracking ? 'BackTrackingSolver' : 'GreedySolver', () {
-      group('basic graph', basicGraph);
-      group('with lockfile', withLockFile);
-      group('root dependency', rootDependency);
-      group('dev dependency', devDependency);
-      group('unsolvable', unsolvable);
-      group('backtracking', backtracking);
-    });
-  }
-
-  // These tests are only valid with the backtracking solver.
-  allowBacktracking = true;
+  group('basic graph', basicGraph);
+  group('with lockfile', withLockFile);
+  group('root dependency', rootDependency);
+  group('dev dependency', devDependency);
+  group('unsolvable', unsolvable);
+  group('backtracking', backtracking);
   group('SDK constraint', sdkConstraint);
 }
 
 void basicGraph() {
   testResolve('no dependencies', {
     'myapp 0.0.0': {}
   }, result: {
     'myapp from root': '0.0.0'
   });
 
@@ skipping 59 matching lines @@
     'foo 1.0.3': { 'zoop': '1.0.0' },
     'bar 1.0.0': { 'foo': '<=1.0.1' },
     'bang 1.0.0': {},
     'whoop 1.0.0': {},
     'zoop 1.0.0': {}
   }, result: {
     'myapp from root': '0.0.0',
     'foo': '1.0.1',
     'bar': '1.0.0',
     'bang': '1.0.0'
-  }, maxTries: 2, hasGreedySolution: true);
+  }, maxTries: 2);
 
   testResolve('circular dependency', {
     'myapp 1.0.0': {
       'foo': '1.0.0'
     },
     'foo 1.0.0': {
       'bar': '1.0.0'
     },
     'bar 1.0.0': {
       'foo': '1.0.0'
@@ skipping 81 matching lines @@
     'bar': '1.0.0',
     'baz': '1.0.0',
     'qux': '1.0.0'
   }, result: {
     'myapp from root': '0.0.0',
     'foo': '2.0.0',
     'bar': '2.0.0',
     'baz': '2.0.0',
     'qux': '1.0.0',
     'newdep': '2.0.0'
-  }, maxTries: 3, hasGreedySolution: true);
+  }, maxTries: 3);
 }
 
 rootDependency() {
   testResolve('with root source', {
     'myapp 1.0.0': {
       'foo': '1.0.0'
     },
     'foo 1.0.0': {
       'myapp from root': '>=1.0.0'
     }
@@ skipping 178 matching lines @@
       'b': '1.0.0'
     },
     'b 1.0.0': {
       'a': '1.0.0'
     }
   }, result: {
     'myapp from root': '0.0.0',
     'a': '1.0.0'
   }, maxTries: 2);
 
-  /// The latest versions of a and b disagree on c. An older version of either
-  /// will resolve the problem. This test validates that b, which is farther
-  /// in the dependency graph from myapp is downgraded first.
+  // The latest versions of a and b disagree on c. An older version of either
+  // will resolve the problem. This test validates that b, which is farther
+  // in the dependency graph from myapp is downgraded first.
   testResolve('rolls back leaf versions first', {
     'myapp 0.0.0': {
       'a': 'any'
     },
     'a 1.0.0': {
       'b': 'any'
     },
     'a 2.0.0': {
       'b': 'any',
       'c': '2.0.0'
@@ skipping 174 matching lines @@
     'bar 3.0.0': {'sdk': badVersion },
     'bar 4.0.0': {'sdk': badVersion }
   }, result: {
     'myapp from root': '0.0.0',
     'foo': '2.0.0',
     'bar': '2.0.0'
   }, maxTries: 3);
 }
 
 testResolve(description, packages,
-            {lockfile, result, FailMatcherBuilder error, int maxTries,
-             bool hasGreedySolution}) {
-  // Close over the top-level variable since it will be mutated.
-  var allowBacktracking_ = allowBacktracking;
-
+            {lockfile, result, FailMatcherBuilder error, int maxTries}) {
   if (maxTries == null) maxTries = 1;
-  if (hasGreedySolution == null) hasGreedySolution = maxTries == 1;
-
-  if (!allowBacktracking_) {
-    // The greedy solver should fail any graph that does expect multiple tries
-    // and isn't explicitly annotated to have a greedy solution.
-    if (!hasGreedySolution) {
-      result = null;
-      error = couldNotSolve;
-    }
-  }
 
   test(description, () {
     var cache = new SystemCache('.');
     source1 = new MockSource('mock1');
     source2 = new MockSource('mock2');
     cache.register(source1);
     cache.register(source2);
     cache.sources.setDefault(source1.name);
 
     // Build the test package graph.
@@ skipping 32 matching lines @@
     if (lockfile != null) {
       lockfile.forEach((name, version) {
         version = new Version.parse(version);
         realLockFile.packages[name] =
           new PackageId(name, source1, version, name);
       });
     }
 
     // Resolve the versions.
     var future = resolveVersions(cache.sources, root,
-        allowBacktracking: allowBacktracking_, lockFile: realLockFile);
+        lockFile: realLockFile);
 
     var matcher;
     if (result != null) {
       matcher = new SolveSuccessMatcher(result, maxTries);
     } else if (error != null) {
       matcher = error(maxTries);
     }
 
     expect(future, completion(matcher));
   });
@@ skipping 281 matching lines @@
   };
 
   var match = new RegExp(r"(.*) from (.*)").firstMatch(description);
   if (match != null) {
     name = match[1];
     source = sourceNames[match[2]];
   }
 
   callback(isDev, name, source);
 }