removed unused imports from Strman.java and split tests out to match current test convention

src/main/java/strman/Strman.java

@@ -38,9 +38,6 @@ import static java.util.function.Function.identity;
 import static java.util.stream.Collectors.counting;
 import static java.util.stream.Collectors.groupingBy;
 import static java.util.stream.Collectors.joining;
-import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertTrue;
-import static strman.Strman.isBlank;
 
 /**
  * A String manipulation library without any dependencies

src/test/java/strman/StrmanTest.java

@@ -1027,9 +1027,17 @@ public class StrmanTest {
     }
     
     @Test
-    public void testIsBlank() {
-    	assertTrue(isBlank(""));
+    public void isBlank_shouldReturnTrueIfNull() {
     	assertTrue(isBlank(null));
+    }
+    
+    @Test
+    public void isBlank_shouldReturnTrueIfEmpty() {
+    	assertTrue(isBlank(""));
+    }
+    
+    @Test
+    public void isBlank_shouldReturnFalseIfNotEmpty() {
     	assertFalse(isBlank("ac"));
     }
 }