Tests for reconstructors

tests/test_reconstructor.py

@@ -0,0 +1,114 @@
+import json
+import unittest
+from unittest import TestCase
+from lark import Lark
+from lark.reconstruct import Reconstructor
+
+
+common = """
+%import common (WS_INLINE, NUMBER, WORD)
+%ignore WS_INLINE
+"""
+
+
+class TestReconstructor(TestCase):
+
+    def reconstruct(self, grammar, code):
+        parser = Lark(grammar, parser='lalr')
+        tree = parser.parse(code)
+        new = Reconstructor(parser).reconstruct(tree)
+        self.assertEqual(code.replace(' ', ''), new.replace(' ', ''))
+
+    def test_starred_rule(self):
+
+        g = """
+        start: item*
+        item: NL
+            | rule
+        rule: WORD ":" NUMBER
+        NL: /(\\r?\\n)+\s*/
+        """ + common
+
+        code = """
+        Elephants: 12
+        """
+
+        self.reconstruct(g, code)
+
+    def test_starred_group(self):
+
+        g = """
+        start: (rule | _NL)*
+        rule: WORD ":" NUMBER
+        _NL: /(\\r?\\n)+\s*/
+        """ + common
+
+        code = """
+        Elephants: 12
+        """
+
+        self.reconstruct(g, code)
+
+    def test_alias(self):
+
+        g = """
+        start: line*
+        line: NL
+            | rule
+            | "hello" -> hi
+        rule: WORD ":" NUMBER
+        NL: /(\\r?\\n)+\s*/
+        """ + common
+
+        code = """
+        Elephants: 12
+        hello
+        """
+
+        self.reconstruct(g, code)
+
+    def test_json_example(self):
+        test_json = '''
+            {
+                "empty_object" : {},
+                "empty_array"  : [],
+                "booleans"     : { "YES" : true, "NO" : false },
+                "numbers"      : [ 0, 1, -2, 3.3, 4.4e5, 6.6e-7 ],
+                "strings"      : [ "This", [ "And" , "That", "And a \\"b" ] ],
+                "nothing"      : null
+            }
+        '''
+
+        json_grammar = r"""
+            ?start: value
+
+            ?value: object
+                  | array
+                  | string
+                  | SIGNED_NUMBER      -> number
+                  | "true"             -> true
+                  | "false"            -> false
+                  | "null"             -> null
+
+            array  : "[" [value ("," value)*] "]"
+            object : "{" [pair ("," pair)*] "}"
+            pair   : string ":" value
+
+            string : ESCAPED_STRING
+
+            %import common.ESCAPED_STRING
+            %import common.SIGNED_NUMBER
+            %import common.WS
+
+            %ignore WS
+        """
+
+        json_parser = Lark(json_grammar, parser='lalr')
+        tree = json_parser.parse(test_json)
+
+        new_json = Reconstructor(json_parser).reconstruct(tree)
+        self.assertEqual(json.loads(new_json), json.loads(test_json))
+
+
+if __name__ == '__main__':
+    unittest.main()