From 539aed32d2381bc75b44c7bae1c014ef60be9ab6 Mon Sep 17 00:00:00 2001
From: Jonathan Leitschuh <Jlleitschuh@wpi.edu>
Date: Thu, 21 Sep 2017 05:20:49 -0400
Subject: [PATCH] Improve information regarding running tests that load
 resources (#1298)

* Improve information regarding running tests that load resources

Figuring out how to run isolated generated tests is not imidiately straightforward.
This clears up confusion by throwing a more helpful error in the tests and
adding a section to the ReadMe.

* Cleanup ReadMe and comments after review feedback
---
 ReadMe.md                                       |  5 +++++
 .../jetbrains/kotlin/test/KotlinTestUtils.java  | 17 ++++++++++++++++-
 2 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/ReadMe.md b/ReadMe.md
index 08d1c6d58a0..6bc7e7d5305 100644
--- a/ReadMe.md
+++ b/ReadMe.md
@@ -127,6 +127,11 @@ Also the [JavaScript translation](https://github.com/JetBrains/kotlin/blob/maste
 
 Some of the code in the standard library is created by generating code from templates. See the [README](libraries/stdlib/ReadMe.md) in the stdlib section for how run the code generator. The existing templates can be used as examples for creating new ones.
 
+### Running specific generated tests
+
+If you need to debug a specific generated test, ensure that you have the `Working directory` in your IntelliJ run configuration set
+to the root directory of this project. If you don't, every test you try to run will fail with a `No such file or directory` exception.
+
 ## Submitting patches
 
 The best way to submit a patch is to [fork the project on github](https://help.github.com/articles/fork-a-repo/) then send us a
diff --git a/compiler/tests-common/org/jetbrains/kotlin/test/KotlinTestUtils.java b/compiler/tests-common/org/jetbrains/kotlin/test/KotlinTestUtils.java
index 00164f1d785..324f4a42ad5 100644
--- a/compiler/tests-common/org/jetbrains/kotlin/test/KotlinTestUtils.java
+++ b/compiler/tests-common/org/jetbrains/kotlin/test/KotlinTestUtils.java
@@ -90,6 +90,7 @@ import org.junit.Assert;
 
 import javax.tools.*;
 import java.io.File;
+import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.io.StringWriter;
 import java.lang.reflect.Method;
@@ -438,7 +439,21 @@ public class KotlinTestUtils {
     }
 
     public static String doLoadFile(@NotNull File file) throws IOException {
-        return FileUtil.loadFile(file, CharsetToolkit.UTF8, true);
+        try {
+            return FileUtil.loadFile(file, CharsetToolkit.UTF8, true);
+        }
+        catch (FileNotFoundException fileNotFoundException) {
+            /*
+             * Unfortunately, the FileNotFoundException will only show the relative path in it's exception message.
+             * This clarifies the exception by showing the full path.
+             */
+            String messageWithFullPath = file.getAbsolutePath() + " (No such file or directory)";
+            throw new IOException(
+                    "Ensure you have your 'Working Directory' configured correctly as the root " +
+                    "Kotlin project directory in your test configuration\n\t" +
+                    messageWithFullPath,
+                    fileNotFoundException);
+        }
     }
 
     public static String getFilePath(File file) {