[ios] Adds unittests for CrashKeyStringBreakpad.

BUG=1061431

Change-Id: I68651bde5441c009c12b400e99ebc615277b3345
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2146934
Commit-Queue: Rohit Rao <rohitrao@chromium.org>
Reviewed-by: Mark Mentovai <mark@chromium.org>
Cr-Commit-Position: refs/heads/master@{#758560}

components/crash/core/common/BUILD.gn

@@ -167,7 +167,11 @@ source_set("unit_tests") {
     sources += [ "objc_zombie_unittest.mm" ]
   }
 
-  if (!is_mac && !is_ios && !is_win && !is_fuchsia && !is_android) {
+  if (is_ios) {
+    sources += [ "crash_key_breakpad_ios_unittest.cc" ]
+    deps += [ "//third_party/breakpad:client" ]
+    include_dirs = [ "//third_party/breakpad/breakpad/src/" ]
+  } else if (!is_mac && !is_win && !is_fuchsia && !is_android) {
     include_dirs = [ "//third_party/breakpad/breakpad/src/" ]
     sources += [ "crash_key_breakpad_unittest.cc" ]
   }

components/crash/core/common/crash_key_breakpad_ios_unittest.cc

+// Copyright 2020 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 "components/crash/core/common/crash_key.h"
+
+#include <string>
+
+#include "testing/gtest/include/gtest/gtest.h"
+#include "testing/platform_test.h"
+#include "third_party/breakpad/breakpad/src/common/simple_string_dictionary.h"
+
+namespace crash_reporter {
+
+namespace {
+
+// The maximum length of a single Breakpad value. Determined by reading the
+// documentation for Breakpad's LongStringDictionary.
+const size_t kMaxValueSize =
+    10 * (google_breakpad::SimpleStringDictionary::value_size - 1);
+
+}  // namespace
+
+class CrashKeyBreakpadIOSTest : public PlatformTest {
+ public:
+  void SetUp() override { InitializeCrashKeysForTesting(); }
+
+  void TearDown() override { ResetCrashKeysForTesting(); }
+};
+
+TEST_F(CrashKeyBreakpadIOSTest, SetClearSingle) {
+  static CrashKeyStringBreakpad<32> key("test-key");
+  EXPECT_FALSE(key.is_set());
+
+  key.Set("value");
+  EXPECT_TRUE(key.is_set());
+  EXPECT_EQ("value", GetCrashKeyValue("test-key"));
+
+  key.Set("value 2");
+  EXPECT_TRUE(key.is_set());
+  EXPECT_EQ("value 2", GetCrashKeyValue("test-key"));
+
+  key.Clear();
+  EXPECT_FALSE(key.is_set());
+  EXPECT_EQ("", GetCrashKeyValue("test-key"));
+}
+
+TEST_F(CrashKeyBreakpadIOSTest, SetMaxLengthValue) {
+  static CrashKeyStringBreakpad<2550> key("test-key");
+
+  key.Set(std::string(kMaxValueSize, 'A'));
+  EXPECT_EQ(kMaxValueSize, GetCrashKeyValue("test-key").length());
+}
+
+TEST_F(CrashKeyBreakpadIOSTest, SetOverflowValue) {
+  static CrashKeyStringBreakpad<4000> key("test-key");
+
+  key.Set(std::string(kMaxValueSize + 100, 'A'));
+  EXPECT_EQ(kMaxValueSize, GetCrashKeyValue("test-key").length());
+}
+
+}  // namespace crash_reporter