diff --git a/src/Transformer.php b/src/Transformer.php
index f6dde8e..0a89042 100644
--- a/src/Transformer.php
+++ b/src/Transformer.php
@@ -111,15 +111,13 @@ private function resolveReference($ref, $context, $root, bool &$found = null) {
             $context = $root;
         }
 
-        if (!is_array($context)) {
-            $found = false;
-            return null;
-        }
-
         $parts = self::explodeRef($ref);
         $result = $context;
         foreach ($parts as $key) {
-            if (array_key_exists($key, $result)) {
+            if (!is_array($result)) {
+                $found = false;
+                return null;
+            } elseif (array_key_exists($key, $result)) {
                 $result = $result[$key];
             } else {
                 $found = false;
@@ -146,7 +144,7 @@ private static function escapeRef(string $field): string {
      * @param string $str The segment to unescapeRef.
      * @return string Returns the unescaped string.
      */
-    public static function unescapeRef(string $str): string {
+    private static function unescapeRef(string $str): string {
         return str_replace(['~2', '~1', '~0'], ['$', '/', '~'], $str);
     }
 
diff --git a/tests/BasicTransformsTest.php b/tests/BasicTransformsTest.php
index 24beae4..7789f1b 100644
--- a/tests/BasicTransformsTest.php
+++ b/tests/BasicTransformsTest.php
@@ -30,8 +30,9 @@ public function testTransform(array $spec, array $expected) {
                 'bar' => 'foo',
             ],
             'a~b' => 'c',
-            'a/b' => 'c',
-            'a$b' => 'c',
+            'a/b' => 'd',
+            'a$b' => 'e',
+            '~/$' => 'f'
         ];
 
         $t = new Transformer($spec);
@@ -51,12 +52,14 @@ public function provideTransformTests(): array {
             'basic ref' => [['foo' => 'nested/bar'], ['foo' => 'foo']],
             'basic nested' => [['nested' => ['foo' => '/foo']], ['nested' => ['foo' => 'baz']]],
             'escape ~' => [['a' => 'a~0b'], ['a' => 'c']],
-            'escape /' => [['a' => 'a~1b'], ['a' => 'c']],
-            'escape $' => [['a' => 'a~2b'], ['a' => 'c']],
+            'escape /' => [['a' => 'a~1b'], ['a' => 'd']],
+            'escape $' => [['a' => 'a~2b'], ['a' => 'e']],
+            'escape all' => [['a' => '~0~1~2'], ['a' => 'f']],
             'not found' => [['a' => 'xdsd'], []],
             'not found default' => [['a' => ['$ref' => 'xdsd', '$default' => 'b']], ['a' => 'b']],
             'literal' => [['a' => ['$literal' => 'abc']], ['a' => 'abc']],
-
+            'escaped dest' => [['a/b' => 'foo'], ['a/b' => 'baz']],
+            'ref to non-array' => [['a' => 'bar/baz'], []],
         ];
 
         return $r;
@@ -67,6 +70,7 @@ public function provideTransformTests(): array {
      *
      * @expectedException \Garden\JSON\InvalidSpecException
      * @expectedExceptionMessageRegExp `^Invalid spec value`
+     * @expectedExceptionCode 500
      */
     public function testInvalidSpec() {
         $t = new Transformer(['foo' => true]);
@@ -79,6 +83,7 @@ public function testInvalidSpec() {
      *
      * @expectedException \Garden\JSON\InvalidSpecException
      * @expectedExceptionMessageRegExp `^Invalid control expression`
+     * @expectedExceptionCode 500
      */
     public function testInvalidControlExpression() {
         $t = new Transformer(['$foo' => 'bar']);
@@ -112,9 +117,23 @@ public function testNumericRelativeArray() {
         $this->assertSame(['b', 'a'], $actual);
     }
 
+    /**
+     * Transformer should be callable on a non-array.
+     */
     public function testNonArrayContext() {
         $t = new Transformer('/foo');
         $actual = $t('baz');
         $this->assertSame(null, $actual);
     }
+
+    /**
+     * Paths should be escaped in error messages.
+     *
+     * @expectedException \Garden\JSON\InvalidSpecException
+     * @expectedExceptionMessage Invalid spec value at /~0~1~2.
+     */
+    public function testEscapePath() {
+        $t = new Transformer(['~/$' => true]);
+        $t(['~/$' => 'a']);
+    }
 }