Add AnalysisCache.flush() utility method.

pkg/analyzer/test/src/context/cache_test.dart

Index: pkg/analyzer/test/src/context/cache_test.dart
diff --git a/pkg/analyzer/test/src/context/cache_test.dart b/pkg/analyzer/test/src/context/cache_test.dart
index 57ff94ea5d9e50cb02029007d88d964ba922c024..2726eefaf23296e50f19d736707f20220352eb42 100644
--- a/pkg/analyzer/test/src/context/cache_test.dart
+++ b/pkg/analyzer/test/src/context/cache_test.dart
@@ -52,6 +52,27 @@ class AnalysisCacheTest extends AbstractCacheTest {
     expect(cache, isNotNull);
   }
 
+  test_flush() {
+    AnalysisTarget target = new TestSource();
+    ResultDescriptor resultA = new ResultDescriptor('A', null);
+    ResultDescriptor resultB = new ResultDescriptor('B', null);
+    CacheEntry entry = new CacheEntry(target);
+    cache.put(entry);
+    // put values
+    entry.setValue(resultA, 'a', TargetedResult.EMPTY_LIST);
+    entry.setValue(resultB, 'b', TargetedResult.EMPTY_LIST);
+    expect(cache.getState(target, resultA), CacheState.VALID);
+    expect(cache.getState(target, resultB), CacheState.VALID);
+    expect(cache.getValue(target, resultA), 'a');
+    expect(cache.getValue(target, resultB), 'b');
+    // flush A
+    cache.flush((target, result) => result == resultA);
+    expect(cache.getState(target, resultA), CacheState.FLUSHED);
+    expect(cache.getState(target, resultB), CacheState.VALID);
+    expect(cache.getValue(target, resultA), isNull);
+    expect(cache.getValue(target, resultB), 'b');
+  }
+
   void test_get() {
     AnalysisTarget target = new TestSource();
     expect(cache.get(target), isNull);
@@ -297,6 +318,27 @@ class CacheEntryTest extends AbstractCacheTest {
     expect(entry.exception, isNull);
   }
 
+  test_flush() {
+    AnalysisTarget target = new TestSource();
+    ResultDescriptor resultA = new ResultDescriptor('A', null);
+    ResultDescriptor resultB = new ResultDescriptor('B', null);
+    CacheEntry entry = new CacheEntry(target);
+    cache.put(entry);
+    // put values
+    entry.setValue(resultA, 'a', TargetedResult.EMPTY_LIST);
+    entry.setValue(resultB, 'b', TargetedResult.EMPTY_LIST);
+    expect(entry.getState(resultA), CacheState.VALID);
+    expect(entry.getState(resultB), CacheState.VALID);
+    expect(entry.getValue(resultA), 'a');
+    expect(entry.getValue(resultB), 'b');
+    // flush A
+    entry.flush((target, result) => result == resultA);
+    expect(entry.getState(resultA), CacheState.FLUSHED);
+    expect(entry.getState(resultB), CacheState.VALID);
+    expect(entry.getValue(resultA), isNull);
+    expect(entry.getValue(resultB), 'b');
+  }
+
   test_getState() {
     AnalysisTarget target = new TestSource();
     ResultDescriptor result = new ResultDescriptor('test', null);