def test_invalid_instr(self):
"""
Tests for invalid op code
"""
e = ElfCPU()
e.load_string('123456789')
with self.assertRaises(InvalidInstructionError):
e.execute()
def test_gpf(self):
"""
Tests for a general protection fault by allowing the program counter to
go past the end of the memory
"""
e = ElfCPU()
e.load_string('1,0,0,0')
with self.assertRaises(ProtectionFaultError):
e.execute()
def test_op_input(self):
"""
Tests input op code
Use unittest.mock.patch to fake the input value
"""
e = ElfCPU()
e.load_string('3,3,99,-1')
with patch('builtins.input', return_value='1234'):
e.execute()
self.assertEqual(e.peek(3), 1234)
def test_op_cmp_lessthan(self):
"""
Tests compare less than op code
"""
e = ElfCPU()
"""
Tests if value of address 5 (5) is less than value of
address 6 (10). Since this is true write 1 to address 7.
"""
e.load_string('7,5,6,7,99,5,10,-1')
e.execute()
self.assertEqual(e.peek(7), 1)
"""
Tests if value of address 5 (10) is less than value of
address 6 (5). Since this is false write 0 to address 7.
"""
e.load_string('7,5,6,7,99,10,5,-1')
e.execute()
self.assertEqual(e.peek(7), 0)
"""
Tests if immediate value of 5 is less than immediate value of
10. Since this is true write 1 to address 7.
"""
e.load_string('1107,5,10,7,99,0,0,-1')
e.execute()
self.assertEqual(e.peek(7), 1)
"""
Tests if immediate value of 10 is less than immediate value of
5. Since this is false write 0 to address 7.
"""
e.load_string('1107,10,5,7,99,0,0,-1')
e.execute()
self.assertEqual(e.peek(7), 0)
def test_op_jmp_true(self):
"""
Tests jump if true op code
"""
e = ElfCPU()
"""
Tests address 8 (which is 1) if it is non-zero. Since this is
true, it jumps to the value of address 9 (which is 7). This
terminates the program.
"""
e.load_string('5,8,9,1101,1,1,8,99,1,7')
e.execute()
self.assertEqual(e.peek(8), 1)
"""
Tests immediate value 8 if it is non-zero. Since it is
true, jump to immediate address 7 which terminates.
"""
e.load_string('1105,8,7,1101,1,1,8,99,1,7')
e.execute()
self.assertEqual(e.peek(8), 1)
"""
Tests address 8 (which is 0) if it is non-zero. Since this is
false it does not jump and instead adds 1+1 to address 8.
"""
e.load_string('5,8,9999,1101,1,1,8,99,0,7')
e.execute()
self.assertEqual(e.peek(8), 2)
"""
Tests immediate value 0 if it is non-zero. Since it is
false it does not jump and instead adds 1+1 to address 8.
"""
e.load_string('1105,0,9999,1101,1,1,8,99,0,7')
e.execute()
self.assertEqual(e.peek(8), 2)
def test_reset(self):
"""
Tests for CPU reset
"""
e = ElfCPU()
e.load_string('1,0,0,0,99')
e.execute()
e.reset()
# Halted gets cleared
self.assertFalse(e.is_halted)
# Program counter goes to 0
self.assertEqual(e.pc, 0)
# Memory gets wiped so address 1 becomes invalid
with self.assertRaises(ValueError):
e.peek(1)
def test_op_output(self):
"""
Tests output op code
Use io.StringIO() to capture the output
"""
e = ElfCPU()
e.load_string('4,5,104,66,99,55')
result = None
with patch('sys.stdout', new=io.StringIO()) as output:
e.execute()
result = output.getvalue()
result = result.splitlines()
# First is a reference to memory address 5
self.assertEqual(result[0].strip(), '55')
# Second is an immediate value
self.assertEqual(result[1].strip(), '66')
def test_op_eq(self):
"""
Tests equals op code
"""
e = ElfCPU()
"""
Tests if value of address 5 (10) is equal to value
of address 6 (10). Since this is true, write 1 to
address 7.
"""
e.load_string('8,5,6,7,99,10,10,-1')
e.execute()
self.assertEqual(e.peek(7), 1)
"""
Tests if value of address 5 (10) is equal to value
of address 6 (0). Since this is false, write 0 to
address 7.
"""
e.load_string('8,5,6,7,99,10,0,-1')
e.execute()
self.assertEqual(e.peek(7), 0)
"""
Tests if immediate value 10 is equal to immediate value
10. Since this is true, write 1 to address 7.
"""
e.load_string('1108,10,10,7,99,2,3,-1')
e.execute()
self.assertEqual(e.peek(7), 1)
"""
Tests if immediate value of 0 is equal to immediate value
10. Since this is false, write 0 to address 7.
"""
e.load_string('1108,0,10,7,99,2,3,-1')
e.execute()
self.assertEqual(e.peek(7), 0)