diff --git a/src/parser/xhpast/__tests__/PHPASTParserTestCase.php b/src/parser/xhpast/__tests__/PHPASTParserTestCase.php
--- a/src/parser/xhpast/__tests__/PHPASTParserTestCase.php
+++ b/src/parser/xhpast/__tests__/PHPASTParserTestCase.php
@@ -80,7 +80,6 @@
 
     switch ($type) {
       case 'pass':
-      case 'fail-parse':
         $this->assertEqual(0, $err, pht('Exit code for "%s".', $name));
 
         if (!strlen($expect)) {
@@ -89,16 +88,6 @@
         }
 
         try {
-          $expect = phutil_json_decode($expect);
-        } catch (PhutilJSONParserException $ex) {
-          throw new PhutilProxyException(
-            pht(
-              'Expect data for test "%s" is not valid JSON.',
-              $name),
-            $ex);
-        }
-
-        try {
           $stdout = phutil_json_decode($stdout);
         } catch (PhutilJSONParserException $ex) {
           throw new PhutilProxyException(
@@ -108,21 +97,16 @@
             $ex);
         }
 
-        $json = new PhutilJSON();
+        $stdout_nice = $this->newReadableAST($stdout, $data);
 
-        $expect_nice = $json->encodeFormatted($expect);
-        $stdout_nice = $json->encodeFormatted($stdout);
+        echo "\n\n\n";
+        echo $stdout_nice;
+        echo "\n\n\n";
 
-        if ($type == 'pass') {
-          $this->assertEqual(
-            $expect_nice,
-            $stdout_nice,
-            pht('Parser output for "%s".', $name));
-        } else {
-          $this->assertFalse(
-            ($expect_nice == $stdout_nice),
-            pht('Expected parser to parse "%s" incorrectly.', $name));
-        }
+        $this->assertEqual(
+          $expect,
+          $stdout_nice,
+          pht('Parser output for "%s".', $name));
         break;
       case 'fail-syntax':
         $this->assertEqual(1, $err, pht('Exit code for "%s".', $name));
@@ -130,7 +114,141 @@
           (bool)preg_match('/syntax error/', $stderr),
           pht('Expect "syntax error" in stderr or "%s".', $name));
         break;
+      default:
+        throw new Exception(
+          pht(
+            'Unknown PHPAST parser test type "%s"!',
+            $type));
+    }
+  }
+
+  /**
+   * Build a human-readable, stable, relatively diff-able string representing
+   * an AST (both the node tree itself and the accompanying token stream) for
+   * use in unit tests.
+   */
+  private function newReadableAST(array $data, $source) {
+    $tree = new XHPASTTree($data['tree'], $data['stream'], $source);
+
+    $out = array();
+    $out[] = $this->newReadableTree($tree);
+    $out[] = $this->newReadableDivider();
+    $out[] = $this->newReadableStream($tree);
+    $out = implode('', $out);
+
+    return $out;
+  }
+
+  private function newReadableTree(XHPASTTree $tree) {
+    $root = $tree->getRootNode();
+
+    $depth = 0;
+    $list = $this->newReadableTreeLines($root, $depth);
+
+    return implode('', $list);
+  }
+
+  private function newReadableDivider() {
+    return str_repeat('-', 80)."\n";
+  }
+
+  private function newReadableStream(XHPASTTree $tree) {
+    $tokens = $tree->getRawTokenStream();
+
+    // Identify the longest token name this stream uses so we can format the
+    // output into two columns.
+    $max_len = 0;
+    foreach ($tokens as $token) {
+      $max_len = max($max_len, strlen($token->getTypeName()));
+    }
+
+    $out = array();
+
+    $tokens = $tree->getRawTokenStream();
+    foreach ($tokens as $token) {
+      $value = $token->getValue();
+      $vector = $this->getEscapedValueVector($value);
+
+      $vector = array_merge(
+        array(
+          str_pad($token->getTypeName(), $max_len),
+          ' ',
+        ),
+        $vector);
+
+      $out[] = $this->wrapVector($vector);
     }
+
+    $out = implode('', $out);
+
+    return $out;
+  }
+
+  private function newReadableTreeLines(AASTNode $node, $depth) {
+    $out = array();
+
+    try {
+      $type_name = $node->getTypeName();
+    } catch (Exception $ex) {
+      $type_name = sprintf('<INVALID TYPE "%s">', $node->getTypeID());
+    }
+
+    $out[] = str_repeat(' ', $depth).'+ '.$type_name."\n";
+
+    $children = $node->getChildren();
+    if ($children) {
+      foreach ($children as $child) {
+        foreach ($this->newReadableTreeLines($child, $depth + 1) as $line) {
+          $out[] = $line;
+        }
+      }
+    } else {
+      $value = $node->getConcreteString();
+      $vector = $this->getEscapedValueVector($value);
+      $out[] = $this->wrapVector($vector, $depth + 1);
+    }
+
+    return $out;
+  }
+
+  private function getEscapedValueVector($value) {
+    if (!$value) {
+      return array('<null>');
+    }
+
+    $vector = phutil_utf8v_combined($value);
+    foreach ($vector as $key => $character) {
+      $vector[$key] = addcslashes($character, "\r\n\t\"\\");
+    }
+
+    return $vector;
+  }
+
+  private function wrapVector(array $vector, $indent = 0, $width = 80) {
+    $lines = array();
+    $prefix = str_repeat(' ', $indent);
+
+    $line = $prefix.'> "';
+    $len = strlen($line);
+    foreach ($vector as $character) {
+      // We're just wrapping based on bytes. This isn't the most correct
+      // wrapping for human language, but sufficient and stable for unit
+      // tests, which will rarely have long sequences of combining or
+      // multibyte characters.
+      $charlen = strlen($character);
+      if ($len + $charlen > ($width - 1)) {
+        $lines[] = $line."\"\n";
+        $line = $prefix.'. "';
+        $len = strlen($line);
+      }
+
+      $line .= $character;
+      $len += $charlen;
+    }
+
+    $lines[] = $line."\"\n";
+
+    return implode('', $lines);
   }
 
 }
diff --git a/src/parser/xhpast/__tests__/data/a-self-test.php.test b/src/parser/xhpast/__tests__/data/a-self-test.php.test
new file mode 100644
--- /dev/null
+++ b/src/parser/xhpast/__tests__/data/a-self-test.php.test
@@ -0,0 +1,60 @@
+<?php
+
+$the_senate = <<<EOTRAGEDY
+Did you ever hear the tragedy of Darth Plagueis The Wise? I
+thought not. It's not a story the Jedi would tell you. It's a Sith legend.
+Darth Plagueis was a Dark Lord of the Sith, so powerful and so wise he could
+use the Force to influence the midichlorians to create life... He had such a
+knowledge of the dark side that he could even keep the ones he cared about from
+dying. The dark side of the Force is a pathway to many abilities some consider
+to be unnatural. He became so powerful... the only thing he was afraid of was
+losing his power, which eventually, of course, he did. Unfortunately, he taught
+his apprentice everything he knew, then his apprentice killed him in his sleep.
+Ironic. He could save others from death, but not himself.
+EOTRAGEDY;
+
+~~~~~~~~~~
+pass
+~~~~~~~~~~
++ n_PROGRAM
+ + n_STATEMENT_LIST
+  + n_OPEN_TAG
+   > "<?php"
+  + n_STATEMENT
+   + n_BINARY_EXPRESSION
+    + n_VARIABLE
+     > "$the_senate"
+    + n_OPERATOR
+     > "="
+    + n_HEREDOC
+     > "<<<EOTRAGEDY\nDid you ever hear the tragedy of Darth Plagueis The Wise?"
+     . " I\nthought not. It's not a story the Jedi would tell you. It's a Sith "
+     . "legend.\nDarth Plagueis was a Dark Lord of the Sith, so powerful and so"
+     . " wise he could\nuse the Force to influence the midichlorians to create "
+     . "life... He had such a\nknowledge of the dark side that he could even ke"
+     . "ep the ones he cared about from\ndying. The dark side of the Force is a"
+     . " pathway to many abilities some consider\nto be unnatural. He became so"
+     . " powerful... the only thing he was afraid of was\nlosing his power, whi"
+     . "ch eventually, of course, he did. Unfortunately, he taught\nhis apprent"
+     . "ice everything he knew, then his apprentice killed him in his sleep.\nI"
+     . "ronic. He could save others from death, but not himself.\nEOTRAGEDY"
+--------------------------------------------------------------------------------
+> "T_OPEN_TAG   <?php"
+> "T_WHITESPACE \n\n"
+> "T_VARIABLE   $the_senate"
+> "T_WHITESPACE  "
+> "=            ="
+> "T_WHITESPACE  "
+> "T_HEREDOC    <<<EOTRAGEDY\nDid you ever hear the tragedy of Darth Plagueis T"
+. "he Wise? I\nthought not. It's not a story the Jedi would tell you. It's a Si"
+. "th legend.\nDarth Plagueis was a Dark Lord of the Sith, so powerful and so w"
+. "ise he could\nuse the Force to influence the midichlorians to create life..."
+. " He had such a\nknowledge of the dark side that he could even keep the ones "
+. "he cared about from\ndying. The dark side of the Force is a pathway to many "
+. "abilities some consider\nto be unnatural. He became so powerful... the only "
+. "thing he was afraid of was\nlosing his power, which eventually, of course, h"
+. "e did. Unfortunately, he taught\nhis apprentice everything he knew, then his"
+. " apprentice killed him in his sleep.\nIronic. He could save others from deat"
+. "h, but not himself.\nEOTRAGEDY"
+> ";            ;"
+> "T_WHITESPACE \n\n"
diff --git a/src/parser/xhpast/__tests__/data/base-fail-parse.php.test b/src/parser/xhpast/__tests__/data/base-fail-parse.php.test
deleted file mode 100644
--- a/src/parser/xhpast/__tests__/data/base-fail-parse.php.test
+++ /dev/null
@@ -1,8 +0,0 @@
-<?php
-~~~~~~~~~~
-fail-parse
-~~~~~~~~~~
-{
-  "tree": [],
-  "stream": []
-}
diff --git a/src/parser/xhpast/__tests__/data/php-heredoc-terminal.php.test b/src/parser/xhpast/__tests__/data/php-heredoc-terminal.php.test
deleted file mode 100644
--- a/src/parser/xhpast/__tests__/data/php-heredoc-terminal.php.test
+++ /dev/null
@@ -1,53 +0,0 @@
-<?php
-<<<HEREDOC
-HEREDOC;
-~~~~~~~~~~
-fail-parse, rtrim
-~~~~~~~~~~
-{
-  "tree": [
-    9000,
-    0,
-    2,
-    [
-      [
-        9006,
-        0,
-        2,
-        [
-          [
-            9007,
-            0,
-            0
-          ],
-          [
-            9004,
-            1,
-            2,
-            [
-              [
-                9098,
-                1,
-                1
-              ]
-            ]
-          ]
-        ]
-      ]
-    ]
-  ],
-  "stream": [
-    [
-      371,
-      6
-    ],
-    [
-      378,
-      18
-    ],
-    [
-      59,
-      1
-    ]
-  ]
-}