Start implementing search support in AnalysisDriver.

pkg/analyzer/test/src/dart/analysis/base.dart

Index: pkg/analyzer/test/src/dart/analysis/base.dart
diff --git a/pkg/analyzer/test/src/dart/analysis/base.dart b/pkg/analyzer/test/src/dart/analysis/base.dart
index a09836dd37554cdc528766dbd8f63785b5602108..ca912ec4144d92b1c46f3e5d57aeb0483d4030c4 100644
--- a/pkg/analyzer/test/src/dart/analysis/base.dart
+++ b/pkg/analyzer/test/src/dart/analysis/base.dart
@@ -13,6 +13,7 @@ import 'package:analyzer/src/dart/analysis/file_state.dart';
 import 'package:analyzer/src/dart/analysis/status.dart';
 import 'package:analyzer/src/generated/engine.dart' show AnalysisOptionsImpl;
 import 'package:analyzer/src/generated/source.dart';
+import 'package:test/test.dart';
 
 import '../../context/mock_sdk.dart';
 
@@ -45,6 +46,33 @@ class BaseAnalysisDriverTest {
     }
   }
 
+  int findOffset(String search) {
+    int offset = testCode.indexOf(search);
+    expect(offset, isNonNegative, reason: "Not found '$search' in\n$testCode");

[Brian Wilkerson, 2016/11/21 21:17:11]

nit: "Not found" --> "Did not find"

+    return offset;
+  }
+
+  int getLeadingIdentifierLength(String search) {
+    int length = 0;
+    while (length < search.length) {
+      int c = search.codeUnitAt(length);
+      if (c >= 'a'.codeUnitAt(0) && c <= 'z'.codeUnitAt(0)) {
+        length++;
+        continue;
+      }
+      if (c >= 'A'.codeUnitAt(0) && c <= 'Z'.codeUnitAt(0)) {
+        length++;
+        continue;
+      }
+      if (c >= '0'.codeUnitAt(0) && c <= '9'.codeUnitAt(0)) {
+        length++;
+        continue;
+      }
+      break;
+    }
+    return length;
+  }
+
   void setUp() {
     new MockSdk();
     testProject = _p('/test/lib');