Add test which reproduce the warning swagger-api#5338

swagger-api#5338 (comment)
`[main] WARN io.swagger.codegen.languages.PhpClientCodegen - Type object not handled properly in setParameterExampleValue`

modules/swagger-codegen/src/test/java/io/swagger/codegen/php/PhpClientExampleTest.java

@@ -0,0 +1,19 @@
+package io.swagger.codegen.php;
+
+import io.swagger.codegen.CodegenParameter;
+import io.swagger.codegen.languages.PhpClientCodegen;
+
+import org.testng.Assert;
+import org.testng.annotations.Test;
+
+public class PhpClientExampleTest {
+    @Test(description = "sets example value")
+    public void exampleValueTest() {
+        PhpClientCodegen clientCodegen = new PhpClientCodegen();
+        CodegenParameter p = new CodegenParameter();
+        p.baseType = "object";
+
+        clientCodegen.setParameterExampleValue(p);
+        Assert.assertEquals(p.example, "new \\stdClass");
+    }
+}