Add tests for compile-time method validation

tests/test_integration.py

@@ -47,6 +47,28 @@ def compile_ct(source: str) -> tuple[int, str, str]:
         os.unlink(ct_file)
 
 
+def compile_ct_check(source: str) -> tuple[int, str, str]:
+    with tempfile.NamedTemporaryFile(mode='w', suffix='.ct', delete=False) as f:
+        f.write(source)
+        f.flush()
+        ct_file = f.name
+
+    sh_file = ct_file.replace('.ct', '.sh')
+
+    try:
+        result = subprocess.run(
+            ['python3', 'content', 'build', ct_file, '-o', sh_file],
+            capture_output=True,
+            text=True,
+            timeout=10
+        )
+        if os.path.exists(sh_file):
+            os.unlink(sh_file)
+        return result.returncode, result.stdout, result.stderr
+    finally:
+        os.unlink(ct_file)
+
+
 class TestPrint:
     def test_print_string(self):
         code, stdout, _ = run_ct('print ("hello")')
@@ -806,3 +828,78 @@ func double(x) {
 print(double(-1))
 ''')
         assert code != 0 or "must be" in stderr
+
+
+class TestMethodValidation:
+    def test_unknown_array_method(self):
+        code, stdout, stderr = compile_ct_check('''
+arr = [1, 2, 3]
+x = arr.nonexistent()
+''')
+        assert code != 0
+        assert "Unknown method 'nonexistent'" in stdout
+        assert "array" in stdout
+
+    def test_unknown_dict_method(self):
+        code, stdout, stderr = compile_ct_check('''
+d = {"key": "value"}
+x = d.nonexistent()
+''')
+        assert code != 0
+        assert "Unknown method 'nonexistent'" in stdout
+        assert "dict" in stdout
+
+    def test_unknown_namespace_method(self):
+        code, stdout, stderr = compile_ct_check('''
+x = fs.nonexistent()
+''')
+        assert code != 0
+        assert "Unknown method 'nonexistent'" in stdout
+        assert "fs" in stdout
+
+    def test_valid_string_methods(self):
+        code, stdout, stderr = compile_ct_check('''
+text = "hello"
+a = text.upper()
+b = text.lower()
+c = text.len()
+d = text.trim()
+''')
+        assert code == 0
+
+    def test_valid_array_methods(self):
+        code, stdout, stderr = compile_ct_check('''
+arr = [1, 2, 3]
+arr.push(4)
+x = arr.pop()
+y = arr.len()
+z = arr.join(" ")
+''')
+        assert code == 0
+
+    def test_valid_dict_methods(self):
+        code, stdout, stderr = compile_ct_check('''
+d = {"key": "value"}
+a = d.get("key")
+d.set("key2", "val2")
+b = d.has("key")
+c = d.keys()
+''')
+        assert code == 0
+
+    def test_valid_namespace_methods(self):
+        code, stdout, stderr = compile_ct_check('''
+x = math.abs(-5)
+y = math.max(1, 2)
+''')
+        assert code == 0
+
+    def test_error_shows_available_methods(self):
+        code, stdout, stderr = compile_ct_check('''
+arr = [1, 2, 3]
+x = arr.foo()
+''')
+        assert code != 0
+        assert "Available:" in stdout
+        assert "push" in stdout
+        assert "pop" in stdout