add exception type to error message in the report (fixes #154)

CHANGELOG.md

@@ -9,6 +9,7 @@ Steps can now have nested steps that are shown in the report. This is done by an
 ### Other
 
 * HTML Report: case tables have sortable columns now [#175](https://github.com/TNG/JGiven/pull/175)
+* Exception type is now added to the error message of a failed step [#154](https://github.com/TNG/JGiven/issues/154)
 
 ## Fixed Issues
 

jgiven-core/src/main/java/com/tngtech/jgiven/impl/ScenarioModelBuilder.java

@@ -199,7 +199,7 @@ public void setSuccess( boolean success ) {
     }
 
     public void setException( Throwable throwable ) {
-        scenarioCaseModel.setErrorMessage( throwable.getMessage() );
+        scenarioCaseModel.setErrorMessage( throwable.getClass().getName() + ": " + throwable.getMessage() );
         scenarioCaseModel.setStackTrace( getStackTrace( throwable, FILTER_STACK_TRACE ) );
     }
 

jgiven-junit/src/test/java/com/tngtech/jgiven/junit/ExceptionReportingTest.java

@@ -0,0 +1,32 @@
+package com.tngtech.jgiven.junit;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import org.junit.Test;
+
+import com.tngtech.jgiven.Stage;
+import com.tngtech.jgiven.StepFunction;
+
+public class ExceptionReportingTest extends SimpleScenarioTest<ExceptionReportingTest.TestSteps> {
+
+    @Test
+    public void exception_type_is_contained_in_the_report() throws Throwable {
+        when().$( "Something", new StepFunction<TestSteps>() {
+            @Override
+            public void apply( TestSteps testSteps ) throws Exception {
+                throw new IllegalStateException( "failing state for testing" );
+            }
+        } );
+
+        try {
+            getScenario().finished();
+        } catch( IllegalStateException ignore ) {}
+
+        String errorMessage = getScenario().getScenarioModel().getCase( 0 ).getErrorMessage();
+        assertThat( errorMessage ).isEqualTo( "java.lang.IllegalStateException: failing state for testing" );
+    }
+
+    public static class TestSteps extends Stage<TestSteps> {
+
+    }
+}