From 1299e51ca6066983b0f543601ec8dbafb8c48569 Mon Sep 17 00:00:00 2001
From: Niklas Keller <me@kelunik.com>
Date: Sun, 11 Dec 2016 17:08:17 +0100
Subject: [PATCH] Add tests for InvalidYieldError, improve key display

Without something like var_export, null and false are casted to an empty string.
---
 lib/InvalidYieldError.php      |  2 +-
 test/InvalidYieldErrorTest.php | 35 ++++++++++++++++++++++++++++++++++
 2 files changed, 36 insertions(+), 1 deletion(-)
 create mode 100644 test/InvalidYieldErrorTest.php

diff --git a/lib/InvalidYieldError.php b/lib/InvalidYieldError.php
index b9d4530..dc02a16 100644
--- a/lib/InvalidYieldError.php
+++ b/lib/InvalidYieldError.php
@@ -12,7 +12,7 @@ class InvalidYieldError extends \Error {
         $prefix .= \sprintf(
             "; %s yielded at key %s",
             \is_object($yielded) ? \get_class($yielded) : \gettype($yielded),
-            $generator->key()
+            \var_export($generator->key(), true)
         );
 
         if (!$generator->valid()) {
diff --git a/test/InvalidYieldErrorTest.php b/test/InvalidYieldErrorTest.php
new file mode 100644
index 0000000..9cbea7b
--- /dev/null
+++ b/test/InvalidYieldErrorTest.php
@@ -0,0 +1,35 @@
+<?php
+
+namespace Amp\Test;
+
+use Amp\InvalidYieldError;
+
+class InvalidYieldErrorTest extends \PHPUnit_Framework_TestCase {
+    public function testWithInvalidGenerator() {
+        /** @var \Generator $gen */
+        $gen = (function () {
+            if (false) {
+                yield;
+            }
+        })();
+
+        $gen->current();
+
+        $error = new InvalidYieldError($gen, "prefix message");
+        $this->assertSame("prefix message; NULL yielded at key NULL", $error->getMessage());
+    }
+
+    public function testSubgenerator() {
+        $subgen = (function () {
+            yield "foo" => 42;
+        })();
+
+        /** @var \Generator $gen */
+        $gen = (function () use ($subgen) {
+            yield from $subgen;
+        })();
+
+        $error = new InvalidYieldError($gen, "prefix");
+        $this->assertSame("prefix; integer yielded at key 'foo' on line " . (__LINE__ - 8) . " in " . __FILE__, $error->getMessage());
+    }
+}
\ No newline at end of file