minor: improve tests failure reporting

libraries/scripting/jvm-host-test/test/kotlin/script/experimental/jvmhost/test/ScriptingHostTest.kt

@@ -197,7 +197,7 @@ class ScriptingHostTest : TestCase() {
             makeSimpleConfigurationWithTestImport()
         }
         val output = captureOut {
-            BasicJvmScriptingHost().eval(script.toScriptSource(), compilationConfiguration, null).throwOnFailure()
+            BasicJvmScriptingHost().eval(script.toScriptSource(), compilationConfiguration, null).throwOnFailure().throwOnExceptionResult()
         }.lines()
         Assert.assertEquals(greeting, output)
     }
@@ -354,7 +354,7 @@ class ScriptingHostTest : TestCase() {
             }
         }
         val output = captureOut {
-            BasicJvmScriptingHost().eval(mainScript, compilationConfiguration, evaluationConfiguration).throwOnFailure()
+            BasicJvmScriptingHost().eval(mainScript, compilationConfiguration, evaluationConfiguration).throwOnFailure().throwOnExceptionResult()
         }.lines()
         return output
     }
@@ -572,6 +572,17 @@ fun <T> ResultWithDiagnostics<T>.throwOnFailure(): ResultWithDiagnostics<T> = ap
     }
 }
 
+fun <T> ResultWithDiagnostics<T>.throwOnExceptionResult(): ResultWithDiagnostics<T> = apply {
+    if (this is ResultWithDiagnostics.Success) {
+        val result = (this.value as? EvaluationResult)
+        val error = (result?.returnValue as? ResultValue.Error)?.error
+        if (error != null) throw Exception(
+            "Evaluation failed:\n  ${reports.joinToString("\n  ") { it.exception?.toString() ?: it.message }}",
+            error
+        )
+    }
+}
+
 private fun evalScript(script: String, host: BasicScriptingHost = BasicJvmScriptingHost()): ResultWithDiagnostics<*> =
     evalScriptWithConfiguration(script, host)
 

plugins/scripting/scripting-compiler/tests/org/jetbrains/kotlin/scripting/compiler/test/ScriptTest.kt

@@ -97,7 +97,7 @@ class ScriptTest : TestCase() {
             return (extraInt(metadata) as Int) and JvmAnnotationNames.METADATA_SCRIPT_FLAG != 0
         }
 
-        val scriptClass = compileScript("metadata_flag.kts", StandardScriptDefinition)!!
+        val scriptClass = compileScript("metadata_flag.kts", StandardScriptDefinition) ?: throw AssertionError("compilation failed")
         assertTrue("Script class SHOULD have the metadata flag set", scriptClass.isFlagSet())
         assertFalse(
             "Non-script class in a script should NOT have the metadata flag set",