Phase 7 step 1

tests/VideoBackendLifecycleTests.cpp

@@ -0,0 +1,96 @@
+#include "VideoBackendLifecycle.h"
+
+#include <iostream>
+#include <string>
+
+namespace
+{
+int gFailures = 0;
+
+void Expect(bool condition, const char* message)
+{
+	if (condition)
+		return;
+
+	std::cerr << "FAIL: " << message << "\n";
+	++gFailures;
+}
+
+void TestAllowedLifecycleTransitions()
+{
+	VideoBackendLifecycle lifecycle;
+	Expect(lifecycle.State() == VideoBackendLifecycleState::Uninitialized, "lifecycle starts uninitialized");
+
+	Expect(lifecycle.TransitionTo(VideoBackendLifecycleState::Discovering, "discover").accepted,
+		"uninitialized can transition to discovering");
+	Expect(lifecycle.TransitionTo(VideoBackendLifecycleState::Discovered, "discovered").accepted,
+		"discovering can transition to discovered");
+	Expect(lifecycle.TransitionTo(VideoBackendLifecycleState::Configuring, "configuring").accepted,
+		"discovered can transition to configuring");
+	Expect(lifecycle.TransitionTo(VideoBackendLifecycleState::Configured, "configured").accepted,
+		"configuring can transition to configured");
+	Expect(lifecycle.TransitionTo(VideoBackendLifecycleState::Prerolling, "preroll").accepted,
+		"configured can transition to prerolling");
+	Expect(lifecycle.TransitionTo(VideoBackendLifecycleState::Running, "running").accepted,
+		"prerolling can transition to running");
+	Expect(lifecycle.TransitionTo(VideoBackendLifecycleState::Degraded, "degraded").accepted,
+		"running can transition to degraded");
+	Expect(lifecycle.TransitionTo(VideoBackendLifecycleState::Running, "recovered").accepted,
+		"degraded can transition back to running");
+	Expect(lifecycle.TransitionTo(VideoBackendLifecycleState::Stopping, "stopping").accepted,
+		"running can transition to stopping");
+	Expect(lifecycle.TransitionTo(VideoBackendLifecycleState::Stopped, "stopped").accepted,
+		"stopping can transition to stopped");
+}
+
+void TestInvalidLifecycleTransitionIsRejected()
+{
+	VideoBackendLifecycle lifecycle;
+	const VideoBackendLifecycleTransition transition =
+		lifecycle.TransitionTo(VideoBackendLifecycleState::Running, "skip setup");
+	Expect(!transition.accepted, "uninitialized cannot transition directly to running");
+	Expect(lifecycle.State() == VideoBackendLifecycleState::Uninitialized, "invalid transition leaves state unchanged");
+	Expect(transition.errorMessage.find("Invalid video backend lifecycle transition") != std::string::npos,
+		"invalid transition reports an error");
+}
+
+void TestFailureStateRecordsReasonAndCanRecover()
+{
+	VideoBackendLifecycle lifecycle;
+	Expect(lifecycle.TransitionTo(VideoBackendLifecycleState::Discovering, "discover").accepted,
+		"lifecycle can start discovery");
+	Expect(lifecycle.Fail("no device").accepted, "discovering can transition to failed");
+	Expect(lifecycle.State() == VideoBackendLifecycleState::Failed, "failure transition sets failed state");
+	Expect(lifecycle.FailureReason() == "no device", "failure reason is retained");
+	Expect(lifecycle.TransitionTo(VideoBackendLifecycleState::Discovering, "retry").accepted,
+		"failed lifecycle can retry discovery");
+	Expect(lifecycle.FailureReason().empty(), "successful non-failed transition clears failure reason");
+}
+
+void TestStateNamesAreStable()
+{
+	Expect(std::string(VideoBackendLifecycle::StateName(VideoBackendLifecycleState::Uninitialized)) == "uninitialized",
+		"uninitialized state name is stable");
+	Expect(std::string(VideoBackendLifecycle::StateName(VideoBackendLifecycleState::Running)) == "running",
+		"running state name is stable");
+	Expect(std::string(VideoBackendLifecycle::StateName(VideoBackendLifecycleState::Failed)) == "failed",
+		"failed state name is stable");
+}
+}
+
+int main()
+{
+	TestAllowedLifecycleTransitions();
+	TestInvalidLifecycleTransitionIsRejected();
+	TestFailureStateRecordsReasonAndCanRecover();
+	TestStateNamesAreStable();
+
+	if (gFailures != 0)
+	{
+		std::cerr << gFailures << " video backend lifecycle test failure(s).\n";
+		return 1;
+	}
+
+	std::cout << "VideoBackendLifecycle tests passed.\n";
+	return 0;
+}