Add a mechanism to force parameters of a group to a specific value.

chrome/common/variations/variations_util_unittest.cc

+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "chrome/common/variations/variations_util.h"
+
+#include "base/metrics/field_trial.h"
+#include "components/variations/variations_associated_data.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace chrome_variations {
+
+class VariationsUtilTest : public ::testing::Test {
+ public:
+  VariationsUtilTest() : field_trial_list_(NULL) {
+  }
+
+  ~VariationsUtilTest() override {
+    // Ensure that the maps are cleared between tests, since they are stored as
+    // process singletons.
+    variations::testing::ClearAllVariationIDs();
+    variations::testing::ClearAllVariationParams();
+  }
+
+ private:
+  base::FieldTrialList field_trial_list_;
+
+  DISALLOW_COPY_AND_ASSIGN(VariationsUtilTest);
+};
+
+TEST_F(VariationsUtilTest, AssociateParamsFromString) {
+  const std::string kTrialName = "AssociateVariationParams";
+  const std::string kVariationsString =
+      "AssociateVariationParams.A:a/10/b/test,AssociateVariationParams.B:a/%2F";
+  ASSERT_TRUE(AssociateParamsFromString(kVariationsString));
+
+  base::FieldTrialList::CreateFieldTrial(kTrialName, "B");
+  EXPECT_EQ("/", variations::GetVariationParamValue(kTrialName, "a"));
+  EXPECT_EQ(std::string(),
+      variations::GetVariationParamValue(kTrialName, "b"));
+  EXPECT_EQ(std::string(),
+      variations::GetVariationParamValue(kTrialName, "x"));
+
+  std::map<std::string, std::string> params;
+  EXPECT_TRUE(variations::GetVariationParams(kTrialName, &params));
+  EXPECT_EQ(1U, params.size());
+  EXPECT_EQ("/", params["a"]);
+}
+
+}  // namespace chrome_variations