Add tests for buildSignature method

Introduced a new test case to verify the buildSignature method with various String class methods and parameter types.

Author: mercyblitz

microsphere-java-core/src/test/java/io/microsphere/reflect/MethodUtilsTest.java

@@ -525,6 +525,13 @@ void testGetSignature() {
         assertEquals("io.microsphere.reflect.MethodUtils#findMethod(java.lang.Class,java.lang.String,java.lang.Class[])", getSignature(method));
     }
 
+    @Test
+    void testBuildSignature() {
+        assertEquals("java.lang.String#toString()", buildSignature(String.class, "toString"));
+        assertEquals("java.lang.String#substring(int)", buildSignature(String.class, "substring", int.class));
+        assertEquals("java.lang.String#substring(int,int)", buildSignature(String.class, "substring", int.class, int.class));
+    }
+
     @Test
     void testIsObjectMethod() {
         assertIsObjectMethod(true, Object.class, "toString");