pkg/unittest: more lock-down, cleanup

pkg/unittest/lib/src/spread_args_helper.dart

+part of unittest;
+
+/** Simulates spread arguments using named arguments. */
+// TODO(sigmund): remove this class and simply use a closure with named
+// arguments (if still applicable).
+class _SpreadArgsHelper {

[Siggi Cherem (dart-lang), 2014/02/03 18:09:46]

wonder if we should rename this. It started with just support for multiple
arguments, but now it's actually mainly the logic to deal with tracking callback
expectations. 

[kevmoo, 2014/02/03 18:22:57]

Sure. But in another CL. I've already spread out the changes here to more than a
few things.

+  final Function callback;
+  final int minExpectedCalls;
+  final int maxExpectedCalls;
+  final Function isDone;
+  final String id;
+  int actualCalls = 0;
+  final TestCase testCase;
+  bool complete;
+  static const sentinel = const _Sentinel();
+
+  _SpreadArgsHelper(Function callback, int minExpected, int maxExpected,
+      Function isDone, String id)
+      : this.callback = callback,
+        minExpectedCalls = minExpected,
+        maxExpectedCalls = (maxExpected == 0 && minExpected > 0)
+            ? minExpected
+            : maxExpected,
+        this.isDone = isDone,
+        this.testCase = currentTestCase,
+        this.id = _makeCallbackId(id, callback) {
+    ensureInitialized();
+    if (testCase == null) {
+      throw new StateError("No valid test. Did you forget to run your test "
+          "inside a call to test()?");
+    }
+
+    if (isDone != null || minExpected > 0) {
+      testCase._callbackFunctionsOutstanding++;
+      complete = false;
+    } else {
+      complete = true;
+    }
+  }
+
+  static String _makeCallbackId(String id, Function callback) {
+    // Try to create a reasonable id.
+    if (id != null) {
+      return "$id ";
+    } else {
+      // If the callback is not an anonymous closure, try to get the
+      // name.
+      var fname = callback.toString();
+      var prefix = "Function '";
+      var pos = fname.indexOf(prefix);
+      if (pos > 0) {
+        pos += prefix.length;
+        var epos = fname.indexOf("'", pos);
+        if (epos > 0) {
+          return "${fname.substring(pos, epos)} ";
+        }
+      }
+    }
+    return '';
+  }
+
+  bool shouldCallBack() {
+    ++actualCalls;
+    if (testCase.isComplete) {
+      // Don't run if the test is done. We don't throw here as this is not
+      // the current test, but we do mark the old test as having an error
+      // if it previously passed.
+      if (testCase.result == PASS) {
+        testCase._error(
+            'Callback ${id}called ($actualCalls) after test case '
+            '${testCase.description} has already been marked as '
+            '${testCase.result}.');
+      }
+      return false;
+    } else if (maxExpectedCalls >= 0 && actualCalls > maxExpectedCalls) {
+      throw new TestFailure('Callback ${id}called more times than expected '
+                            '($maxExpectedCalls).');
+    }
+    return true;
+  }
+
+  void after() {
+    if (!complete) {
+      if (minExpectedCalls > 0 && actualCalls < minExpectedCalls) return;
+      if (isDone != null && !isDone()) return;
+
+      // Mark this callback as complete and remove it from the testcase
+      // oustanding callback count; if that hits zero the testcase is done.
+      complete = true;
+      testCase._markCallbackComplete();
+    }
+  }
+
+  invoke0() {
+    return _guardAsync(
+        () {
+          if (shouldCallBack()) {
+            return callback();
+          }
+        },
+        after, testCase);
+  }
+
+  invoke1(arg1) {
+    return _guardAsync(
+        () {
+          if (shouldCallBack()) {
+            return callback(arg1);
+          }
+        },
+        after, testCase);
+  }
+
+  invoke2(arg1, arg2) {
+    return _guardAsync(
+        () {
+          if (shouldCallBack()) {
+            return callback(arg1, arg2);
+          }
+        },
+        after, testCase);
+  }
+}