allow ResultHeaderItem to have empty name

Author: jimirocks

src/main/java/com/gooddata/executeafm/result/ResultHeaderItem.java

@@ -9,7 +9,7 @@
 import com.fasterxml.jackson.annotation.JsonTypeInfo;
 import com.gooddata.util.GoodDataToStringBuilder;
 
-import static com.gooddata.util.Validate.notEmpty;
+import static com.gooddata.util.Validate.notNull;
 
 /**
  * Represent header items available in {@link ExecutionResult}
@@ -25,7 +25,7 @@ public abstract class ResultHeaderItem {
     private final String name;
 
     protected ResultHeaderItem(final String name) {
-        this.name = notEmpty(name, "name");
+        this.name = notNull(name, "name");
     }
 
     /**

src/test/groovy/com/gooddata/executeafm/result/ResultHeaderItemTest.groovy

@@ -25,4 +25,17 @@ class ResultHeaderItemTest extends Specification {
         typeClass << [AttributeHeaderItem, ResultMeasureHeaderItem, ResultTotalHeaderItem]
         type = typeClass.simpleName.uncapitalize()
     }
+
+    def "should allow empty name"() {
+        expect:
+        new ResultHeaderItem('') {}.name == ''
+    }
+
+    def "should not allow null name"() {
+        when:
+        new ResultHeaderItem(null) {}
+
+        then:
+        thrown(IllegalArgumentException)
+    }
 }