Use the new error reporting to figure out exactly what was wrong.

Author: nedtwigg

lib-extra/src/test/java/com/diffplug/spotless/extra/groovy/GrEclipseFormatterStepSpecialCaseTest.java

@@ -15,16 +15,30 @@
  */
 package com.diffplug.spotless.extra.groovy;
 
+import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.api.Test;
 
 import com.diffplug.spotless.StepHarness;
 import com.diffplug.spotless.TestProvisioner;
 
 public class GrEclipseFormatterStepSpecialCaseTest {
-	/** https://github.com/diffplug/spotless/issues/1657 */
+	/**
+	 * https://github.com/diffplug/spotless/issues/1657
+	 *
+	 * broken: ${parm == null ? "" : "<tag>$parm</tag>"}
+	 *  works: ${parm == null ? "" : "<tag>parm</tag>"}
+	 */
 	@Test
 	public void issue_1657() {
+		Assertions.assertThrows(IllegalArgumentException.class, () -> {
+			StepHarness.forStep(GrEclipseFormatterStep.createBuilder(TestProvisioner.mavenCentral()).build())
+					.testResourceUnaffected("groovy/greclipse/format/SomeClass.test");
+		});
+	}
+
+	@Test
+	public void issue_1657_fixed() {
 		StepHarness.forStep(GrEclipseFormatterStep.createBuilder(TestProvisioner.mavenCentral()).build())
-				.testResourceUnaffected("groovy/greclipse/format/SomeClass.test");
+				.testResourceUnaffected("groovy/greclipse/format/SomeClass.fixed");
 	}
 }

testlib/src/main/resources/groovy/greclipse/format/SomeClass.fixed

@@ -0,0 +1,12 @@
+package com.somepackage
+
+class SomeClass {
+
+	def func(parm) {
+		"""<tag>
+            ${parm == null ? "" : "<tag>parm</tag>"}
+            ${parm == null ? "" : "<tag>parm</tag>"}
+           </tag>
+        """
+	}
+}

testlib/src/main/resources/groovy/greclipse/format/SomeClass.test

@@ -6,7 +6,7 @@ class SomeClass {
         """<tag>
             ${parm == null ? "" : "<tag>$parm</tag>"}
             ${parm == null ? "" : "<tag>$parm</tag>"}
-            </tag>
+           </tag>
         """
     }
 }