Update string util test cases to include other whitespaces

Author: psx95

api/test/common/string_util_test.cc

@@ -35,9 +35,15 @@ TEST(StringUtilTest, TrimString)
                    {"k1=v1,k2=v2, k3=v3", "k1=v1,k2=v2, k3=v3"},
                    {"   k1=v1", "k1=v1"},
                    {"k1=v1   ", "k1=v1"},
+                   {"k1=v1\t", "k1=v1"},
+                   {"\t k1=v1 \t", "k1=v1"},
+                   {"\t\t k1=v1\t  ", "k1=v1"},
+                   {"\t\t k1=v1\t  ,k2=v2", "k1=v1\t  ,k2=v2"},
                    {"   k1=v1 ", "k1=v1"},
                    {" ", ""},
-                   {"", ""}};
+                   {"", ""},
+                   {"\n_some string_\t", "_some string_"}};
+
   for (auto &testcase : testcases)
   {
     EXPECT_EQ(StringUtil::Trim(testcase.input), testcase.expected);