Add test which loads firmware during warmboot

Summary:
In prod, we plan to enable/update FW across a warm boot
via config change. Add a test to test loading the FW across a warm boot

Reviewed By: shri-khare

Differential Revision: D68816000

fbshipit-source-id: ecccc4310d759ca5e4d92fead13d9f360f4b5f3a

fboss/agent/test/AgentHwTest.h

@@ -40,7 +40,7 @@ class AgentHwTest : public ::testing::Test {
   ~AgentHwTest() override = default;
   void SetUp() override;
   void TearDown() override;
-  void tearDownAgentEnsemble(bool doWarmboot = false);
+  virtual void tearDownAgentEnsemble(bool doWarmboot = false);
   using StateUpdateFn = SwSwitch::StateUpdateFn;
 
  protected:

fboss/agent/test/agent_hw_tests/AgentVoqSwitchFirmwareTests.cpp

@@ -146,6 +146,36 @@ class AgentVoqSwitchIsolationFirmwareTest : public AgentVoqSwitchTest {
   }
 };
 
+class AgentVoqSwitchIsolationFirmwareUpdateTest
+    : public AgentVoqSwitchIsolationFirmwareTest {
+ public:
+  cfg::SwitchConfig initialConfig(
+      const AgentEnsemble& ensemble) const override {
+    auto config = utility::onePortPerInterfaceConfig(
+        ensemble.getSw(),
+        ensemble.masterLogicalPortIds(),
+        true, /*interfaceHasSubnet*/
+        true, /*setInterfaceMac*/
+        utility::kBaseVlanId,
+        true /*enable fabric ports*/);
+    utility::populatePortExpectedNeighborsToSelf(
+        ensemble.masterLogicalPortIds(), config);
+    return config;
+  }
+  void tearDownAgentEnsemble(bool warmboot = false) override {
+    // We check for agentEnsemble not being NULL since the tests
+    // are also invoked for just listing their prod features.
+    // Then in such case, agentEnsemble is never setup
+    if (getAgentEnsemble() && getSw()->getBootType() == BootType::COLD_BOOT) {
+      auto agentConfig = getSw()->getAgentConfig();
+      const auto& configFileName = getAgentEnsemble()->configFileName();
+      agentConfig.sw() = addFwConfig(*agentConfig.sw());
+      AgentEnsemble::writeConfig(agentConfig, configFileName);
+    }
+    AgentHwTest::tearDownAgentEnsemble(warmboot);
+  }
+};
+
 TEST_F(AgentVoqSwitchIsolationFirmwareTest, forceIsolate) {
   auto setup = [this]() {
     assertPortAndDrainState(false /* not drained*/);
@@ -212,4 +242,18 @@ TEST_F(AgentVoqSwitchIsolationFirmwareTest, forceCrashDuringWarmBoot) {
   auto verifyPostWarmboot = [this]() { forceIsolatePostCrashAndVerify(); };
   verifyAcrossWarmBoots(setup, []() {}, []() {}, verifyPostWarmboot);
 }
+
+TEST_F(AgentVoqSwitchIsolationFirmwareUpdateTest, loadOnWarmboot) {
+  auto setup = [this]() {
+    assertPortAndDrainState(false /* not drained*/);
+    setMinLinksConfig();
+  };
+
+  auto verifyPostWarmboot = [this]() {
+    forceIsolate();
+    assertSwitchDrainState(true /* drained */);
+  };
+  verifyAcrossWarmBoots(setup, []() {}, []() {}, verifyPostWarmboot);
+}
+
 } // namespace facebook::fboss