diff --git a/trunk/src/utest/srs_utest.cpp b/trunk/src/utest/srs_utest.cpp
index ec5eee727..06b69e118 100644
--- a/trunk/src/utest/srs_utest.cpp
+++ b/trunk/src/utest/srs_utest.cpp
@@ -129,3 +129,11 @@ VOID TEST(SampleTest, FastSampleMacrosTest)
     EXPECT_NEAR(10, 15, 5);
 }
 
+VOID TEST(SampleTest, StringEQTest)
+{
+    string str = "100";
+    EXPECT_TRUE("100" == str);
+    EXPECT_EQ("100", str);
+    EXPECT_STREQ("100", str.c_str());
+}
+
diff --git a/trunk/src/utest/srs_utest_app.cpp b/trunk/src/utest/srs_utest_app.cpp
index 0be744239..25f63af95 100644
--- a/trunk/src/utest/srs_utest_app.cpp
+++ b/trunk/src/utest/srs_utest_app.cpp
@@ -36,7 +36,7 @@ VOID TEST(AppCoroutineTest, Dummy)
     SrsDummyCoroutine dc;
 
     if (true) {
-        EXPECT_EQ(0, dc.cid());
+        EXPECT_EQ("", dc.cid());
 
         srs_error_t err = dc.pull();
         EXPECT_TRUE(err != srs_success);
@@ -52,7 +52,7 @@ VOID TEST(AppCoroutineTest, Dummy)
     if (true) {
         dc.stop();
 
-        EXPECT_EQ(0, dc.cid());
+        EXPECT_EQ("", dc.cid());
 
         srs_error_t err = dc.pull();
         EXPECT_TRUE(err != srs_success);
@@ -68,7 +68,7 @@ VOID TEST(AppCoroutineTest, Dummy)
     if (true) {
         dc.interrupt();
 
-        EXPECT_EQ(0, dc.cid());
+        EXPECT_EQ("", dc.cid());
 
         srs_error_t err = dc.pull();
         EXPECT_TRUE(err != srs_success);
@@ -92,7 +92,7 @@ public:
     // Quit without error.
     bool quit;
 public:
-    MockCoroutineHandler() : trd(NULL), err(srs_success), cid(0), quit(false) {
+    MockCoroutineHandler() : trd(NULL), err(srs_success), cid("0"), quit(false) {
         running = srs_cond_new();
         exited = srs_cond_new();
     }
@@ -128,12 +128,12 @@ VOID TEST(AppCoroutineTest, StartStop)
         MockCoroutineHandler ch;
         SrsSTCoroutine sc("test", &ch);
         ch.trd = ≻
-        EXPECT_EQ(0, sc.cid());
+        EXPECT_EQ("", sc.cid());
 
         // Thread stop after created.
         sc.stop();
 
-        EXPECT_EQ(0, sc.cid());
+        EXPECT_EQ("", sc.cid());
 
         srs_error_t err = sc.pull();
         EXPECT_TRUE(srs_success != err);
@@ -151,13 +151,13 @@ VOID TEST(AppCoroutineTest, StartStop)
         MockCoroutineHandler ch;
         SrsSTCoroutine sc("test", &ch);
         ch.trd = ≻
-        EXPECT_EQ(0, sc.cid());
+        EXPECT_EQ("", sc.cid());
 
         EXPECT_TRUE(srs_success == sc.start());
         EXPECT_TRUE(srs_success == sc.pull());
 
         srs_cond_timedwait(ch.running, 100 * SRS_UTIME_MILLISECONDS);
-        EXPECT_TRUE(sc.cid() > 0);
+        EXPECT_TRUE(!sc.cid().empty());
 
         // Thread stop after started.
         sc.stop();
@@ -178,7 +178,7 @@ VOID TEST(AppCoroutineTest, StartStop)
         MockCoroutineHandler ch;
         SrsSTCoroutine sc("test", &ch);
         ch.trd = ≻
-        EXPECT_EQ(0, sc.cid());
+        EXPECT_EQ("", sc.cid());
 
         EXPECT_TRUE(srs_success == sc.start());
         EXPECT_TRUE(srs_success == sc.pull());
@@ -220,16 +220,16 @@ VOID TEST(AppCoroutineTest, Cycle)
 
     if (true) {
         MockCoroutineHandler ch;
-        SrsSTCoroutine sc("test", &ch, 250);
+        SrsSTCoroutine sc("test", &ch, "250");
         ch.trd = ≻
-        EXPECT_EQ(250, sc.cid());
+        EXPECT_TRUE("250" == sc.cid());
 
         EXPECT_TRUE(srs_success == sc.start());
         EXPECT_TRUE(srs_success == sc.pull());
 
         // After running, the cid in cycle should equal to the thread.
         srs_cond_timedwait(ch.running, 100 * SRS_UTIME_MILLISECONDS);
-        EXPECT_EQ(250, ch.cid);
+        EXPECT_TRUE("250" == ch.cid);
     }
 
     if (true) {
diff --git a/trunk/src/utest/srs_utest_kernel.cpp b/trunk/src/utest/srs_utest_kernel.cpp
index 720c8b624..bc0109ef1 100644
--- a/trunk/src/utest/srs_utest_kernel.cpp
+++ b/trunk/src/utest/srs_utest_kernel.cpp
@@ -4106,9 +4106,9 @@ VOID TEST(KernelLogTest, CoverAll)
         l.error("TAG", "0", "log");
         
         ISrsThreadContext ctx;
-        ctx.set_id(10);
-        EXPECT_EQ("0", ctx.get_id());
-        EXPECT_EQ("0", ctx.generate_id());
+        ctx.set_id("10");
+        EXPECT_EQ("", ctx.get_id());
+        EXPECT_EQ("", ctx.generate_id());
     }
 }
 
diff --git a/trunk/src/utest/srs_utest_service.cpp b/trunk/src/utest/srs_utest_service.cpp
index 1385852a4..3611fd41e 100644
--- a/trunk/src/utest/srs_utest_service.cpp
+++ b/trunk/src/utest/srs_utest_service.cpp
@@ -782,7 +782,7 @@ class MockOnCycleThread : public ISrsCoroutineHandler
 public:
     SrsSTCoroutine trd;
     srs_cond_t cond;
-    MockOnCycleThread() : trd("mock", this, 0) {
+    MockOnCycleThread() : trd("mock", this, "0") {
         cond = srs_cond_new();
     };
     virtual ~MockOnCycleThread() {
@@ -822,7 +822,7 @@ class MockOnCycleThread2 : public ISrsCoroutineHandler
 public:
     SrsSTCoroutine trd;
     srs_mutex_t lock;
-    MockOnCycleThread2() : trd("mock", this, 0) {
+    MockOnCycleThread2() : trd("mock", this, "0") {
         lock = srs_mutex_new();
     };
     virtual ~MockOnCycleThread2() {
@@ -863,7 +863,7 @@ class MockOnCycleThread3 : public ISrsCoroutineHandler
 public:
     SrsSTCoroutine trd;
     srs_netfd_t fd;
-    MockOnCycleThread3() : trd("mock", this, 0) {
+    MockOnCycleThread3() : trd("mock", this, "0") {
         fd = NULL;
     };
     virtual ~MockOnCycleThread3() {
@@ -1116,7 +1116,7 @@ class MockOnCycleThread4 : public ISrsCoroutineHandler
 public:
     SrsSTCoroutine trd;
     srs_netfd_t fd;
-    MockOnCycleThread4() : trd("mock", this, 0) {
+    MockOnCycleThread4() : trd("mock", this, "0") {
         fd = NULL;
     };
     virtual ~MockOnCycleThread4() {
@@ -1268,18 +1268,18 @@ VOID TEST(TCPServerTest, ContextUtility)
     if (true) {
         SrsThreadContext ctx;
 
-        EXPECT_EQ("0", ctx.set_id("100"));
-        EXPECT_EQ("100", ctx.set_id("1000"));
-        EXPECT_EQ("1000", ctx.get_id());
+        EXPECT_TRUE("" == ctx.set_id("100"));
+        EXPECT_TRUE("100" == ctx.set_id("1000"));
+        EXPECT_TRUE("1000" == ctx.get_id());
 
         ctx.clear_cid();
-        EXPECT_EQ("0", ctx.set_id("100"));
+        EXPECT_TRUE("" == ctx.set_id("100"));
     }
 
     int base_size = 0;
     if (true) {
         int size = 0; char buf[1024]; HELPER_ARRAY_INIT(buf, 1024, 0);
-        ASSERT_TRUE(srs_log_header(buf, 1024, true, true, "SRS", 100, "Trace", &size));
+        ASSERT_TRUE(srs_log_header(buf, 1024, true, true, "SRS", "100", "Trace", &size));
         base_size = size;
         EXPECT_TRUE(base_size > 0);
     }