Fixed #8. Added support for isLowerCase function

src/main/java/strman/Strman.java

@@ -493,6 +493,17 @@ public abstract class Strman {
         return append(value.substring(0, index), substr, value.substring(index));
     }
 
+    /**
+     * Verifies if String is lower case
+     *
+     * @param value The input String
+     * @return true if String is lowercase false otherwise
+     */
+    public static boolean isLowerCase(final String value) {
+        validate(value, NULL_STRING_PREDICATE, NULL_STRING_MSG_SUPPLIER);
+        return Objects.equals(value, value.toLowerCase());
+    }
+
     public static String leftPad(final String value, final String pad, final int length) {
         validate(value, NULL_STRING_PREDICATE, NULL_STRING_MSG_SUPPLIER);
         if (value.length() >= length) {

src/test/java/strman/StrmanTest.java

@@ -396,4 +396,17 @@ public class StrmanTest {
         assertThat(insert("foobar", "x", 6), equalTo("foobarx"));
         assertThat(insert("foo bar", "asadasd", 100), equalTo("foo bar"));
     }
+
+    @Test
+    public void isLowerCase_shouldBeTrueWhenStringIsLowerCase() throws Exception {
+        assertThat(isLowerCase(""), equalTo(true));
+        assertThat(isLowerCase("foo"), equalTo(true));
+        assertThat(isLowerCase("foobarfoo"), equalTo(true));
+    }
+
+    @Test
+    public void isLowerCase_shouldBeFalseWhenStringIsNotLowerCase() throws Exception {
+        assertThat(isLowerCase("Foo"), equalTo(false));
+        assertThat(isLowerCase("foobarfooA"), equalTo(false));
+    }
 }