| 1 | """Testing tools for byterun."""
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| 2 |
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| 3 | from __future__ import print_function
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| 4 |
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| 5 | import dis
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| 6 | import sys
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| 7 | import textwrap
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| 8 | import types
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| 9 | import unittest
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| 10 |
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| 11 | import six
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| 12 |
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| 13 | from pyvm2 import VirtualMachine, VirtualMachineError
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| 14 |
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| 15 | # Make this false if you need to run the debugger inside a test.
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| 16 | CAPTURE_STDOUT = ('-s' not in sys.argv)
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| 17 | # Make this false to see the traceback from a failure inside pyvm2.
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| 18 | CAPTURE_EXCEPTION = 1
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| 19 |
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| 20 |
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| 21 | def dis_code(code):
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| 22 | """Disassemble `code` and all the code it refers to."""
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| 23 | for const in code.co_consts:
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| 24 | if isinstance(const, types.CodeType):
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| 25 | dis_code(const)
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| 26 |
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| 27 | print("")
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| 28 | print(code)
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| 29 | dis.dis(code)
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| 30 |
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| 31 |
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| 32 | class VmTestCase(unittest.TestCase):
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| 33 |
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| 34 | def assert_ok(self, code, raises=None):
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| 35 | """Run `code` in our VM and in real Python: they behave the same."""
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| 36 |
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| 37 | code = textwrap.dedent(code)
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| 38 | code = compile(code, "<%s>" % self.id(), "exec", 0, 1)
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| 39 |
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| 40 | # Print the disassembly so we'll see it if the test fails.
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| 41 | dis_code(code)
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| 42 |
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| 43 | real_stdout = sys.stdout
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| 44 |
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| 45 | # Run the code through our VM.
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| 46 |
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| 47 | vm_stdout = six.StringIO()
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| 48 | if CAPTURE_STDOUT: # pragma: no branch
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| 49 | sys.stdout = vm_stdout
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| 50 | vm = VirtualMachine()
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| 51 |
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| 52 | vm_value = vm_exc = None
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| 53 | try:
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| 54 | vm_value = vm.run_code(code)
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| 55 | except VirtualMachineError: # pragma: no cover
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| 56 | # If the VM code raises an error, show it.
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| 57 | raise
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| 58 | except AssertionError: # pragma: no cover
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| 59 | # If test code fails an assert, show it.
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| 60 | raise
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| 61 | except Exception as e:
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| 62 | # Otherwise, keep the exception for comparison later.
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| 63 | if not CAPTURE_EXCEPTION: # pragma: no cover
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| 64 | raise
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| 65 | vm_exc = e
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| 66 | finally:
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| 67 | real_stdout.write("-- stdout ----------\n")
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| 68 | real_stdout.write(vm_stdout.getvalue())
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| 69 |
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| 70 | # Run the code through the real Python interpreter, for comparison.
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| 71 |
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| 72 | py_stdout = six.StringIO()
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| 73 | sys.stdout = py_stdout
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| 74 |
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| 75 | py_value = py_exc = None
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| 76 | globs = {}
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| 77 | try:
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| 78 | py_value = eval(code, globs, globs)
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| 79 | except AssertionError: # pragma: no cover
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| 80 | raise
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| 81 | except Exception as e:
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| 82 | py_exc = e
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| 83 |
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| 84 | sys.stdout = real_stdout
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| 85 |
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| 86 | self.assert_same_exception(vm_exc, py_exc)
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| 87 | self.assertEqual(vm_stdout.getvalue(), py_stdout.getvalue())
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| 88 | self.assertEqual(vm_value, py_value)
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| 89 | if raises:
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| 90 | self.assertIsInstance(vm_exc, raises)
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| 91 | else:
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| 92 | self.assertIsNone(vm_exc)
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| 93 |
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| 94 | def assert_same_exception(self, e1, e2):
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| 95 | """Exceptions don't implement __eq__, check it ourselves."""
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| 96 | self.assertEqual(str(e1), str(e2))
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| 97 | self.assertIs(type(e1), type(e2))
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