class LoxTests_Execute_Statements(unittest.TestCase):
def setUp(self):
self.output = TestOutputStream()
self.lox = Lox(output = self.output)
def test_print_literal(self):
self.lox.execute('print "yo";')
self.assertEqual(self.output.last_sent, "yo")
class LoxTests_LogicalOperators(unittest.TestCase):
def setUp(self):
self.output = TestOutputStream()
self.lox = Lox(output = self.output)
def test_print_false_and_1(self):
self.lox.execute('print false and 1;')
self.assertEqual(self.output.last_sent, False)
def test_print_true_and_1(self):
self.lox.execute('print true and 1;')
self.assertEqual(self.output.last_sent, 1)
class LoxTests_Scoping(unittest.TestCase):
def setUp(self):
self.output = TestOutputStream()
self.lox = Lox(output = self.output)
def test_reuse_name_in_inner_scope(self):
self.lox.execute('var a = 1;')
self.lox.execute('{ var a = 2; print a; }')
self.assertEqual(self.output.last_sent, 2)
self.lox.execute('print a;')
self.assertEqual(self.output.last_sent, 1)
def test_assign_outer_in_inner_scope(self):
self.lox.execute('var a = 1;')
self.lox.execute('{ a = 2; }')
self.lox.execute('print a;')
self.assertEqual(self.output.last_sent, 2)
class LoxTests_WhileLoops(unittest.TestCase):
def setUp(self):
self.output = TestOutputStream()
self.lox = Lox(output = self.output)
def test_while_var_one_loop(self):
self.lox.execute('var do_loop = true;')
self.lox.execute('while (do_loop) { print 1; do_loop = false; }')
self.assertEqual(self.output.last_sent, 1)
def test_while_false_does_nothing(self):
self.lox.execute('while (false) print 1;')
self.assertEqual(self.output.num_sent(), 0)
def test_while_loops_multiple_times(self):
self.lox.execute('var temp = 5;')
self.lox.execute('while (temp > 0) { print 1; temp = temp - 1; }')
self.assertEqual(self.output.num_sent(), 5)
class LoxTests_Execute_Expressions(unittest.TestCase):
def setUp(self):
self.output = TestOutputStream()
self.lox = Lox(output = self.output)
def test_numerical(self):
params = [
('1 + 1', 2),
('2 * 2', 4),
('1 + 4 / 2', 3),
('(1 + 4) / 2', 2.5),
(""" ( 1 + 4/2) * 3*2 - 10
== ( 1 + 2) * 6 - 10 """, True),
]
for expression, expected in params:
with self.subTest():
self.lox.execute(f'print {expression};')
self.assertEqual(self.output.last_sent, expected)
def test_strings(self):
params = [
('"cat" == "cat"', True),
('"dog" == "cat"', False)
]
for expression, expected in params:
with self.subTest():
self.lox.execute(f'print {expression};')
self.assertEqual(self.output.last_sent, expected)
def test_bools(self):
params = [
('true == 1 < 2', True),
('false != 1 < 2 + 4', True)
]
for expression, expected in params:
with self.subTest():
self.lox.execute(f'print {expression};')
self.assertEqual(self.output.last_sent, expected)
def test_incomplete_expression(self):
self.lox.execute('1 +')
self.assertTrue('Expected expression' in self.output.last_sent)
class LoxTests_IfElse(unittest.TestCase):
def setUp(self):
self.output = TestOutputStream()
self.lox = Lox(output = self.output)
def test_if_true_else(self):
self.lox.execute('if (true) print "true"; else print "false";')
self.assertEqual(self.output.last_sent, "true")
def test_if_false_else(self):
self.lox.execute('if (false) print "true"; else print "false";')
self.assertEqual(self.output.last_sent, "false")
def test_nested_if_else_should_grab_earliest_else(self):
self.lox.execute("""
if (true)
if (true)
print "this should get printed";
else
print "this should not get printed";
""")
self.assertEqual(self.output.last_sent, "this should get printed")
class LoxTests_Variables(unittest.TestCase):
def setUp(self):
self.output = TestOutputStream()
self.lox = Lox(output = self.output)
def test_declare_then_print(self):
self.lox.execute('var a;')
self.lox.execute('print a;')
self.assertEqual(self.output.last_sent, "nil")
def test_declare_with_initialiser_then_print(self):
self.lox.execute('var a = 1;')
self.lox.execute('print a;')
self.assertEqual(self.output.last_sent, 1)
def test_declare_with_initialiser_expression_then_print(self):
self.lox.execute('var a = 1 + 1;')
self.lox.execute('print a;')
self.assertEqual(self.output.last_sent, 2)
def test_declare_then_assign(self):
self.lox.execute('var a = 1;')
self.lox.execute('print a;')
self.assertEqual(self.output.last_sent, 1)
self.lox.execute('a = "asdf";')
self.lox.execute('print a;')
self.assertEqual(self.output.last_sent, 'asdf')
def test_can_print_assignment(self):
# assignment is an expression, so has a value
self.lox.execute('var a = 1;')
self.lox.execute('print a = 2;')
self.assertEqual(self.output.last_sent, 2)
def test_bad_assign_target_should_print_error(self):
self.lox.execute('var a; var b;')
self.lox.execute('a + b = 3;')
self.assertIn('Invalid assignment target', self.output.last_sent)