added test for string strip

moco-core/src/test/java/com/github/dreamhead/moco/util/StringUtilTest.java

@@ -0,0 +1,43 @@
+package com.github.dreamhead.moco.util;
+
+import org.junit.Test;
+
+import static com.github.dreamhead.moco.util.StringUtil.strip;
+import static org.hamcrest.CoreMatchers.is;
+import static org.junit.Assert.assertThat;
+
+public class StringUtilTest {
+    @Test
+    public void should_strip_null_to_empty_string() {
+        assertThat(strip(null), is(""));
+    }
+
+    @Test
+    public void should_strip_empty_to_empty_string() {
+        assertThat(strip(""), is(""));
+    }
+
+    @Test
+    public void should_strip_ordinary_string_as_it_is() {
+        assertThat(strip("foo"), is("foo"));
+        assertThat(strip("bar"), is("bar"));
+    }
+
+    @Test
+    public void should_strip_string_with_leading_whitespace() {
+        assertThat(strip(" foo"), is("foo"));
+        assertThat(strip("  bar"), is("bar"));
+    }
+
+    @Test
+    public void should_strip_string_with_end_whitespace() {
+        assertThat(strip("foo "), is("foo"));
+        assertThat(strip("bar  "), is("bar"));
+    }
+
+    @Test
+    public void should_strip_string_with_both_leading_and_end_whitespace() {
+        assertThat(strip(" foo "), is("foo"));
+        assertThat(strip("  bar  "), is("bar"));
+    }
+}