diff --git a/test/fixtures/test_grammars/inlined_aliased_rules/grammar.js b/test/fixtures/test_grammars/inlined_aliased_rules/grammar.js
new file mode 100644
index 00000000..8578659b
--- /dev/null
+++ b/test/fixtures/test_grammars/inlined_aliased_rules/grammar.js
@@ -0,0 +1,28 @@
+module.exports = grammar({
+  name: "inlined_aliased_rules",
+
+  extras: $ => [/\s/],
+
+  inline: $ => [$.expression],
+
+  rules: {
+    statement: $ => seq($.expression, ";"),
+
+    expression: $ =>
+      choice(
+        $.call_expression,
+        $.member_expression,
+        alias($.identifier, $.variable_name),
+      ),
+
+    call_expression: $ => prec.left(seq($.expression, "(", $.expression, ")")),
+
+    member_expression: $ =>
+      prec.left(
+        1,
+        seq($.expression, ".", alias($.identifier, $.property_name)),
+      ),
+
+    identifier: $ => /[a-z]+/,
+  },
+});
diff --git a/test/fixtures/test_grammars/inlined_aliased_rules/grammar.json b/test/fixtures/test_grammars/inlined_aliased_rules/grammar.json
deleted file mode 100644
index d98f6e6c..00000000
--- a/test/fixtures/test_grammars/inlined_aliased_rules/grammar.json
+++ /dev/null
@@ -1,75 +0,0 @@
-{
-  "name": "inlined_aliased_rules",
-
-  "extras": [
-    {"type": "PATTERN", "value": "\\s"}
-  ],
-
-  "inline": [
-    "expression"
-  ],
-
-  "rules": {
-    "statement": {
-      "type": "SEQ",
-      "members": [
-        {"type": "SYMBOL", "name": "expression"},
-        {"type": "STRING", "value": ";"}
-      ]
-    },
-
-    "expression": {
-      "type": "CHOICE",
-      "members": [
-        {"type": "SYMBOL", "name": "call_expression"},
-        {"type": "SYMBOL", "name": "member_expression"},
-        {
-          "type": "ALIAS",
-          "value": "variable_name",
-          "named": true,
-          "content": {
-            "type": "SYMBOL",
-            "name": "identifier"
-          }
-        }
-      ]
-    },
-
-    "call_expression": {
-      "type": "PREC_LEFT",
-      "value": 0,
-      "content": {
-        "type": "SEQ",
-        "members": [
-          {"type": "SYMBOL", "name": "expression"},
-          {"type": "STRING", "value": "("},
-          {"type": "SYMBOL", "name": "expression"},
-          {"type": "STRING", "value": ")"}
-        ]
-      }
-    },
-
-    "member_expression": {
-      "type": "PREC_LEFT",
-      "value": 1,
-      "content": {
-        "type": "SEQ",
-        "members": [
-          {"type": "SYMBOL", "name": "expression"},
-          {"type": "STRING", "value": "."},
-          {
-            "type": "ALIAS",
-            "named": true,
-            "value": "property_name",
-            "content": {
-              "type": "SYMBOL",
-              "name": "identifier"
-            }
-          }
-        ]
-      }
-    },
-
-    "identifier": {"type": "PATTERN", "value": "[a-z]+"}
-  }
-}
diff --git a/test/fixtures/test_grammars/inverted_external_token/grammar.js b/test/fixtures/test_grammars/inverted_external_token/grammar.js
new file mode 100644
index 00000000..3530d0db
--- /dev/null
+++ b/test/fixtures/test_grammars/inverted_external_token/grammar.js
@@ -0,0 +1,15 @@
+module.exports = grammar({
+  name: "inverted_external_token",
+
+  externals: $ => [$.line_break],
+
+  extras: $ => [/\s/],
+
+  rules: {
+    program: $ => repeat($.statement),
+    statement: $ => seq($._expression, $.line_break),
+    _expression: $ => choice($.identifier, $.member_expression),
+    member_expression: $ => prec.left(seq($._expression, ".", $.identifier)),
+    identifier: $ => /[a-z]+/,
+  },
+});
diff --git a/test/fixtures/test_grammars/inverted_external_token/grammar.json b/test/fixtures/test_grammars/inverted_external_token/grammar.json
deleted file mode 100644
index 6dee3d03..00000000
--- a/test/fixtures/test_grammars/inverted_external_token/grammar.json
+++ /dev/null
@@ -1,55 +0,0 @@
-{
-  "name": "inverted_external_token",
-
-  "externals": [
-    {"type": "SYMBOL", "name": "line_break"}
-  ],
-
-  "extras": [
-    {"type": "PATTERN", "value": "\\s"}
-  ],
-
-  "rules": {
-    "program": {
-      "type": "REPEAT",
-      "content": {
-        "type": "SYMBOL",
-        "name": "statement"
-      }
-    },
-
-    "statement": {
-      "type": "SEQ",
-      "members": [
-        {"type": "SYMBOL", "name": "_expression"},
-        {"type": "SYMBOL", "name": "line_break"}
-      ]
-    },
-
-    "_expression": {
-      "type": "CHOICE",
-      "members": [
-        {"type": "SYMBOL", "name": "identifier"},
-        {"type": "SYMBOL", "name": "member_expression"}
-      ]
-    },
-
-    "member_expression": {
-      "type": "PREC_LEFT",
-      "value": 0,
-      "content": {
-        "type": "SEQ",
-        "members": [
-          {"type": "SYMBOL", "name": "_expression"},
-          {"type": "STRING", "value": "."},
-          {"type": "SYMBOL", "name": "identifier"}
-        ]
-      }
-    },
-
-    "identifier": {
-      "type": "PATTERN",
-      "value": "[a-z]+"
-    }
-  }
-}
diff --git a/test/fixtures/test_grammars/invisible_start_rule/grammar.js b/test/fixtures/test_grammars/invisible_start_rule/grammar.js
new file mode 100644
index 00000000..4afa4d66
--- /dev/null
+++ b/test/fixtures/test_grammars/invisible_start_rule/grammar.js
@@ -0,0 +1,8 @@
+module.exports = grammar({
+  name: "invisible_start_rule",
+  rules: {
+    _value: $ => choice($.a, $.b),
+    a: $ => "a",
+    b: $ => "b",
+  },
+});
diff --git a/test/fixtures/test_grammars/invisible_start_rule/grammar.json b/test/fixtures/test_grammars/invisible_start_rule/grammar.json
deleted file mode 100644
index 809624bd..00000000
--- a/test/fixtures/test_grammars/invisible_start_rule/grammar.json
+++ /dev/null
@@ -1,23 +0,0 @@
-{
-  "name": "invisible_start_rule",
-
-  "rules": {
-    "_value": {
-      "type": "CHOICE",
-      "members": [
-        {"type": "SYMBOL", "name": "a"},
-        {"type": "SYMBOL", "name": "b"}
-      ]
-    },
-
-    "a": {
-      "type": "STRING",
-      "value": "a"
-    },
-
-    "b": {
-      "type": "STRING",
-      "value": "b"
-    }
-  }
-}
\ No newline at end of file