tests: parser: add parser tests

compiler/tests/test_parser.py

@@ -0,0 +1,55 @@
+from __future__ import annotations
+
+import io
+
+# noinspection PyUnresolvedReferences
+from compiler import semantic
+from compiler.lexer import Tokens, Lexer, TextIOWithMemory
+from compiler.parser import Parser
+
+
+def _lex_string(data: str) -> Lexer:
+    return Lexer(input_stream=TextIOWithMemory(io.StringIO(data)),
+                 token_filter=lambda token: token.kind not in [Tokens.Blank, Tokens.Newline, Tokens.Comment])
+
+
+def test_parser_empty():
+    lexer = _lex_string("")
+    my_parser = Parser(tokens=lexer)
+    node = my_parser.parse()
+    assert node._pretty(indent=" ").strip() == """
+    Block(pure=True) {
+  BEGIN(None)
+  EOF(None)
+ } // Block""".strip()
+
+
+def test_parser_arithmetic():
+    lexer = _lex_string("""
+    1+5-41*2/1;
+    """)
+    my_parser = Parser(tokens=lexer)
+    node = my_parser.parse()
+    assert node._pretty(indent=" ").strip() == """
+    Block(pure=True) {
+  Statement(pure=True) {
+   Expression(pure=True) {
+    Sub(pure=True) {
+     Sum(pure=True) {
+      Integer(1)
+      Integer(5)
+     } // Sum
+     TrueDivision(pure=True) {
+      Product(pure=True) {
+       Integer(41)
+       Integer(2)
+      } // Product
+      Integer(1)
+     } // TrueDivision
+    } // Sub
+   } // Expression
+   PseudoNode(';')
+  } // Statement
+  BEGIN(None)
+  EOF(None)
+ } // Block""".strip()