test(thread): add gtests for ProfiledThread park state

Author: kaahos

ddprof-lib/src/test/cpp/park_state_ut.cpp

@@ -0,0 +1,63 @@
+/*
+ * Copyright 2026 Datadog, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <gtest/gtest.h>
+#include "thread.h"
+
+TEST(ProfiledThreadParkStateTest, ParkFlagLifecycle) {
+  ProfiledThread* thread = ProfiledThread::forTid(12345);
+
+  EXPECT_FALSE(thread->isParkedForWallclock());
+
+  thread->parkEnter(101, 202, 777);
+  EXPECT_TRUE(thread->isParkedForWallclock());
+
+  u64 start_ticks = 0;
+  Context park_context = {};
+  EXPECT_TRUE(thread->parkExit(start_ticks, park_context));
+  EXPECT_EQ(777ULL, start_ticks);
+  EXPECT_EQ(101ULL, park_context.spanId);
+  EXPECT_EQ(202ULL, park_context.rootSpanId);
+  EXPECT_FALSE(thread->isParkedForWallclock());
+
+  // Second exit is a no-op once the parked bit is cleared.
+  EXPECT_FALSE(thread->parkExit(start_ticks, park_context));
+}
+
+TEST(ProfiledThreadParkStateTest, ParkEnterSnapshotsTagEncodings) {
+  ProfiledThread* thread = ProfiledThread::forTid(12346);
+  u32* tags = thread->getOtelTagEncodingsPtr();
+  tags[0] = 11;
+  tags[1] = 22;
+  tags[2] = 33;
+
+  thread->parkEnter(303, 404, 888);
+
+  // Mutate live encodings after enter: park context must keep the enter snapshot.
+  tags[0] = 111;
+  tags[1] = 222;
+  tags[2] = 333;
+
+  u64 start_ticks = 0;
+  Context park_context = {};
+  ASSERT_TRUE(thread->parkExit(start_ticks, park_context));
+  EXPECT_EQ(888ULL, start_ticks);
+  EXPECT_EQ(303ULL, park_context.spanId);
+  EXPECT_EQ(404ULL, park_context.rootSpanId);
+  EXPECT_EQ(11U, park_context.tags[0].value);
+  EXPECT_EQ(22U, park_context.tags[1].value);
+  EXPECT_EQ(33U, park_context.tags[2].value);
+}