diff --git a/ssl/test/runner/common.go b/ssl/test/runner/common.go
index f22f95a..9af3063 100644
--- a/ssl/test/runner/common.go
+++ b/ssl/test/runner/common.go
@@ -449,6 +449,10 @@
 	// SkipCipherVersionCheck causes the server to negotiate
 	// TLS 1.2 ciphers in earlier versions of TLS.
 	SkipCipherVersionCheck bool
+
+	// ExpectServerName, if not empty, is the hostname the client
+	// must specify in the server_name extension.
+	ExpectServerName string
 }
 
 func (c *Config) serverInit() {
diff --git a/ssl/test/runner/handshake_server.go b/ssl/test/runner/handshake_server.go
index 6d61fd5..e456891 100644
--- a/ssl/test/runner/handshake_server.go
+++ b/ssl/test/runner/handshake_server.go
@@ -237,6 +237,9 @@
 	if len(hs.clientHello.serverName) > 0 {
 		hs.cert = config.getCertificateForName(hs.clientHello.serverName)
 	}
+	if expected := c.config.Bugs.ExpectServerName; expected != "" && expected != hs.clientHello.serverName {
+		return false, errors.New("tls: unexpected server name")
+	}
 
 	if hs.clientHello.channelIDSupported && config.RequestChannelID {
 		hs.hello.channelIDRequested = true
diff --git a/ssl/test/runner/runner.go b/ssl/test/runner/runner.go
index 64df21d..ae74464 100644
--- a/ssl/test/runner/runner.go
+++ b/ssl/test/runner/runner.go
@@ -202,36 +202,6 @@
 		flags: []string{"-fallback-scsv"},
 	},
 	{
-		testType: serverTest,
-		name:     "ServerNameExtension",
-		config: Config{
-			ServerName: "example.com",
-		},
-		flags: []string{"-expect-server-name", "example.com"},
-	},
-	{
-		testType: clientTest,
-		name:     "DuplicateExtensionClient",
-		config: Config{
-			Bugs: ProtocolBugs{
-				DuplicateExtension: true,
-			},
-		},
-		shouldFail:         true,
-		expectedLocalError: "remote error: error decoding message",
-	},
-	{
-		testType: serverTest,
-		name:     "DuplicateExtensionServer",
-		config: Config{
-			Bugs: ProtocolBugs{
-				DuplicateExtension: true,
-			},
-		},
-		shouldFail:         true,
-		expectedLocalError: "remote error: error decoding message",
-	},
-	{
 		name: "ClientCertificateTypes",
 		config: Config{
 			ClientAuth: RequestClientCert,
@@ -1372,6 +1342,73 @@
 	})
 }
 
+func addExtensionTests() {
+	testCases = append(testCases, testCase{
+		testType: clientTest,
+		name:     "DuplicateExtensionClient",
+		config: Config{
+			Bugs: ProtocolBugs{
+				DuplicateExtension: true,
+			},
+		},
+		shouldFail:         true,
+		expectedLocalError: "remote error: error decoding message",
+	})
+	testCases = append(testCases, testCase{
+		testType: serverTest,
+		name:     "DuplicateExtensionServer",
+		config: Config{
+			Bugs: ProtocolBugs{
+				DuplicateExtension: true,
+			},
+		},
+		shouldFail:         true,
+		expectedLocalError: "remote error: error decoding message",
+	})
+	testCases = append(testCases, testCase{
+		testType: clientTest,
+		name:     "ServerNameExtensionClient",
+		config: Config{
+			Bugs: ProtocolBugs{
+				ExpectServerName: "example.com",
+			},
+		},
+		flags: []string{"-host-name", "example.com"},
+	})
+	testCases = append(testCases, testCase{
+		testType: clientTest,
+		name:     "ServerNameExtensionClient",
+		config: Config{
+			Bugs: ProtocolBugs{
+				ExpectServerName: "mismatch.com",
+			},
+		},
+		flags:              []string{"-host-name", "example.com"},
+		shouldFail:         true,
+		expectedLocalError: "tls: unexpected server name",
+	})
+	testCases = append(testCases, testCase{
+		testType: clientTest,
+		name:     "ServerNameExtensionClient",
+		config: Config{
+			Bugs: ProtocolBugs{
+				ExpectServerName: "missing.com",
+			},
+		},
+		shouldFail:         true,
+		expectedLocalError: "tls: unexpected server name",
+	})
+	testCases = append(testCases, testCase{
+		testType: serverTest,
+		name:     "ServerNameExtensionServer",
+		config: Config{
+			ServerName: "example.com",
+		},
+		flags:         []string{"-expect-server-name", "example.com"},
+		resumeSession: true,
+	})
+}
+
 func worker(statusChan chan statusMsg, c chan *testCase, buildDir string, wg *sync.WaitGroup) {
 	defer wg.Done()
 
@@ -1425,6 +1462,7 @@
 	addClientAuthTests()
 	addVersionNegotiationTests()
 	addD5BugTests()
+	addExtensionTests()
 	for _, async := range []bool{false, true} {
 		for _, splitHandshake := range []bool{false, true} {
 			for _, protocol := range []protocol{tls, dtls} {