diff --git a/test/oemrouter_unittest.cpp b/test/oemrouter_unittest.cpp
new file mode 100644
index 0000000..a5a79dd
--- /dev/null
+++ b/test/oemrouter_unittest.cpp
@@ -0,0 +1,175 @@
+#include "host-ipmid/ipmid-api.h"
+#include "host-ipmid/oemrouter.hpp"
+#include "sample.h"
+
+#include <cstring>
+#include <gtest/gtest.h>
+
+// Watch for correct singleton behavior.
+static oem::Router* singletonUnderTest;
+
+static ipmid_callback_t wildHandler;
+
+static ipmi_netfn_t lastNetFunction;
+
+// Fake ipmi_register_callback() for this test.
+void ipmi_register_callback(ipmi_netfn_t netfn, ipmi_cmd_t cmd,
+                            ipmi_context_t context, ipmid_callback_t cb,
+                            ipmi_cmd_privilege_t priv)
+{
+    EXPECT_EQ(NETFUN_OEM_GROUP, netfn);
+    EXPECT_EQ(IPMI_CMD_WILDCARD, cmd);
+    EXPECT_EQ(reinterpret_cast<void*>(singletonUnderTest), context);
+    EXPECT_EQ(PRIVILEGE_OEM, priv);
+    lastNetFunction = netfn;
+    wildHandler = cb;
+}
+
+namespace oem
+{
+
+namespace
+{
+void MakeRouter()
+{
+    if (!singletonUnderTest)
+    {
+        singletonUnderTest = mutableRouter();
+    }
+    ASSERT_EQ(singletonUnderTest, mutableRouter());
+}
+
+void ActivateRouter()
+{
+    MakeRouter();
+    singletonUnderTest->activate();
+    ASSERT_EQ(NETFUN_OEM_GROUP, lastNetFunction);
+}
+
+void RegisterWithRouter(Number oen, ipmi_cmd_t cmd, Handler cb)
+{
+    ActivateRouter();
+    singletonUnderTest->registerHandler(oen, cmd, cb);
+}
+
+uint8_t msgPlain[] = { 0x56, 0x34, 0x12 };
+uint8_t replyPlain[] = { 0x56, 0x34, 0x12, 0x31, 0x41 };
+uint8_t msgPlus2[] = { 0x67, 0x45, 0x23, 0x10, 0x20 };
+uint8_t msgBadOen[] = { 0x57, 0x34, 0x12 };
+
+void RegisterTwoWays(ipmi_cmd_t *nextCmd)
+{
+    Handler f = [](ipmi_cmd_t cmd, const uint8_t* reqBuf,
+                   uint8_t* replyBuf, size_t* dataLen)
+    {
+        // Check inputs
+        EXPECT_EQ(0x78, cmd);
+        EXPECT_EQ(0, *dataLen);  // Excludes OEN
+
+        // Generate reply.
+        *dataLen = 2;
+        std::memcpy(replyBuf, replyPlain + 3, *dataLen);
+        return 0;
+    };
+    RegisterWithRouter(0x123456, 0x78, f);
+
+    *nextCmd = IPMI_CMD_WILDCARD;
+    Handler g = [nextCmd](ipmi_cmd_t cmd, const uint8_t* reqBuf,
+                          uint8_t* replyBuf, size_t* dataLen)
+    {
+        // Check inputs
+        EXPECT_EQ(*nextCmd, cmd);
+        EXPECT_EQ(2, *dataLen);  // Excludes OEN
+        if (2 != *dataLen)
+        {
+            return 0xE0;
+        }
+        EXPECT_EQ(msgPlus2[3], reqBuf[0]);
+        EXPECT_EQ(msgPlus2[4], reqBuf[1]);
+
+        // Generate reply.
+        *dataLen = 0;
+        return 0;
+    };
+    RegisterWithRouter(0x234567, IPMI_CMD_WILDCARD, g);
+}
+}  // namespace
+
+TEST(OemRouterTest, MakeRouterProducesConsistentSingleton) {
+    MakeRouter();
+}
+
+TEST(OemRouterTest, ActivateRouterSetsLastNetToOEMGROUP) {
+    lastNetFunction = 0;
+    ActivateRouter();
+}
+
+TEST(OemRouterTest, VerifiesSpecificCommandMatches) {
+    ipmi_cmd_t cmd;
+    uint8_t reply[256];
+    size_t dataLen;
+
+    RegisterTwoWays(&cmd);
+
+    dataLen = 3;
+    EXPECT_EQ(0,
+              wildHandler(NETFUN_OEM_GROUP, 0x78, msgPlain, reply,
+                          &dataLen, nullptr));
+    EXPECT_EQ(5, dataLen);
+    EXPECT_EQ(replyPlain[0], reply[0]);
+    EXPECT_EQ(replyPlain[1], reply[1]);
+    EXPECT_EQ(replyPlain[2], reply[2]);
+    EXPECT_EQ(replyPlain[3], reply[3]);
+    EXPECT_EQ(replyPlain[4], reply[4]);
+}
+
+TEST(OemRouterTest, WildCardMatchesTwoRandomCodes) {
+    ipmi_cmd_t cmd;
+    uint8_t reply[256];
+    size_t dataLen;
+
+    RegisterTwoWays(&cmd);
+
+    // Check two random command codes.
+    dataLen = 5;
+    cmd = 0x89;
+    EXPECT_EQ(0,
+              wildHandler(NETFUN_OEM_GROUP, cmd, msgPlus2, reply,
+                          &dataLen, nullptr));
+    EXPECT_EQ(3, dataLen);
+
+    dataLen = 5;
+    cmd = 0x67;
+    EXPECT_EQ(0,
+              wildHandler(NETFUN_OEM_GROUP, cmd, msgPlus2, reply,
+                          &dataLen, nullptr));
+    EXPECT_EQ(3, dataLen);
+}
+
+TEST(OemRouterTest, CommandsAreRejectedIfInvalid) {
+    ipmi_cmd_t cmd;
+    uint8_t reply[256];
+    size_t dataLen;
+
+    RegisterTwoWays(&cmd);
+
+    // Message too short to include whole OEN?
+    dataLen = 2;
+    EXPECT_EQ(IPMI_CC_REQ_DATA_LEN_INVALID,
+              wildHandler(NETFUN_OEM_GROUP, 0x78, msgPlain, reply,
+                          &dataLen, nullptr));
+
+    // Wrong specific command?
+    dataLen = 3;
+    EXPECT_EQ(IPMI_CC_INVALID,
+              wildHandler(NETFUN_OEM_GROUP, 0x89, msgPlain, reply,
+                          &dataLen, nullptr));
+
+    // Wrong OEN?
+    dataLen = 3;
+    EXPECT_EQ(IPMI_CC_INVALID,
+              wildHandler(NETFUN_OEM_GROUP, 0x78, msgBadOen, reply,
+                          &dataLen, nullptr));
+}
+
+}  // namespace oem