Start making comprehensive calc tests

common/lib/calc/tests/test_calc.py

+"""
+unittests for calc.py
+
+Run like this:
+
+    rake test_common/lib/calc ??
+
+"""
+
+import unittest
+import numpy
+import calc
+
+
+class EvaluatorTest(unittest.TestCase):
+    ''' Run tests for calc.evaluator
+    Go through all functionalities as specifically as possible--
+    work from number input to functions and complex expressions
+    Also test custom variable substitutions (i.e.
+      `evaluator({'x':3.0},{}, '3*x')`
+    gives 9.0) and more.
+    '''
+
+    def test_number_input(self):
+        ''' Test different kinds of float inputs '''
+        easy_eval = lambda x: calc.evaluator({}, {}, x)
+
+        self.assertEqual(easy_eval("13"), 13)
+        self.assertEqual(easy_eval("3.14"), 3.14)
+        self.assertEqual(easy_eval(".618033989"), 0.618033989)
+
+        self.assertEqual(easy_eval("-13"), -13)
+        self.assertEqual(easy_eval("-3.14"), -3.14)
+        self.assertEqual(easy_eval("-.618033989"), -0.618033989)
+        # see also test_exponential_answer
+        # and test_si_suffix
+
+    def test_exponential_answer(self):
+        ''' Test for correct interpretation of scientific notation'''
+        answer = 50
+        correct_responses = ["50", "50.0", "5e1", "5e+1", "50e0", "50.0e0", "500e-1"]
+        incorrect_responses = ["", "3.9", "4.1", "0", "5.01e1"]
+
+        for input_str in correct_responses:
+            result = calc.evaluator({}, {}, input_str)
+            fail_msg = "Failed when checking '{0}' against {1} (expected equality)".format(
+                input_str, answer)
+            self.assertEqual(answer, result, msg=fail_msg)
+
+        for input_str in incorrect_responses:
+            result = calc.evaluator({}, {}, input_str)
+            fail_msg = "Failed when checking '{0}' against {1} (expected inequality)".format(
+                input_str, answer)
+            self.assertNotEqual(answer, result, msg=fail_msg)
+
+    def test_si_suffix(self):
+        ''' Test calc.py's unique functionality of interpreting si 'suffixes'.
+        For instance 'k' stand for 'kilo-' so '1k' should be 1,000 '''
+        test_mapping = [('4.2%', 0.042), ('2.25k', 2250), ('8.3M', 8300000),
+                        ('9.9G', 9.9e9), ('1.2T', 1.2e12), ('7.4c', 0.074),
+                        ('5.4m', 0.0054), ('8.7u', 0.0000087),
+                        ('5.6n', 5.6e-9), ('4.2p', 4.2e-12)]
+
+        for (expr, answer) in test_mapping:
+            tolerance = answer * 1e-6  # Testing exactly fails for the large values
+            fail_msg = "Failure in testing suffix '{0}': '{1}' was not {2}".format(
+                expr[-1], expr, answer)
+            self.assertAlmostEqual(calc.evaluator({}, {}, expr), answer,
+                                   delta=tolerance, msg=fail_msg)
+
+    def test_operator_sanity(self):
+        ''' Test for simple things like "5+2" and "5/2"'''
+        var1 = 5.0
+        var2 = 2.0
+        operators = [('+', 7), ('-', 3), ('*', 10), ('/', 2.5), ('^', 25)]
+
+        for (operator, answer) in operators:
+            input_str = "{0} {1} {2}".format(var1, operator, var2)
+            result = calc.evaluator({}, {}, input_str)
+            fail_msg = "Failed on operator '{0}': '{1}' was not {2}".format(
+                operator, input_str, answer)
+            self.assertEqual(answer, result, msg=fail_msg)
+
+        self.assertRaises(ZeroDivisionError, calc.evaluator,
+                          {}, {}, '1/0')
+
+    def test_parallel_resistors(self):
+        ''' Test the special operator ||
+        The formula is given by
+            a || b || c ...
+            = 1 / (1/a + 1/b + 1/c + ...)
+        It is the resistance of a parallel circuit of resistors with resistance
+        a, b, c, etc&. See if this evaulates correctly.'''
+        self.assertEqual(calc.evaluator({}, {}, '1||1'), 0.5)
+        self.assertEqual(calc.evaluator({}, {}, '1||1||2'), 0.4)
+
+        # I don't know why you would want this, but it works.
+        self.assertEqual(calc.evaluator({}, {}, "j||1"), 0.5 + 0.5j)
+
+        self.assertRaises(ZeroDivisionError, calc.evaluator,
+                          {}, {}, '0||1')
+
+
+    def assert_function_values(self, fname, ins, outs, tolerance=1e-3):
+        ''' Helper function to test many values at once
+        Test the accuracy of evaluator's use of the function given by fname
+        Specifically, the equality of `fname(ins[i])` against outs[i].
+        Used later to test a whole bunch of f(x) = y at a time '''
+
+        for (arg, val) in zip(ins, outs):
+            input_str = "{0}({1})".format(fname, arg)
+            result = calc.evaluator({}, {}, input_str)
+            fail_msg = "Failed on function {0}: '{1}' was not {2}".format(
+                fname, input_str, val)
+            self.assertAlmostEqual(val, result, delta=tolerance, msg=fail_msg)
+
+    def test_trig_functions(self):
+        """Test the trig functions provided in common/lib/calc/calc.py"""
+        # which are: sin, cos, tan, arccos, arcsin, arctan
+
+        angles = ['-pi/4', '0', 'pi/6', 'pi/5', '5*pi/4', '9*pi/4', 'j', '1 + j']
+        sin_values = [-0.707, 0, 0.5, 0.588, -0.707, 0.707, 1.175j, 1.298 + 0.635j]
+        cos_values = [0.707, 1, 0.866, 0.809, -0.707, 0.707, 1.543, 0.834 - 0.989j]
+        tan_values = [-1, 0, 0.577, 0.727, 1, 1, 0.762j, 0.272 + 1.084j]
+        # Cannot test tan(pi/2) b/c pi/2 is a float and not precise...
+
+        self.assert_function_values('sin', angles, sin_values)
+        self.assert_function_values('cos', angles, cos_values)
+        self.assert_function_values('tan', angles, tan_values)
+
+        # include those where the real part is between -pi/2 and pi/2
+        arcsin_inputs = ['-0.707', '0', '0.5', '0.588', '1.298 + 0.635*j']
+        arcsin_angles = [-0.785, 0, 0.524, 0.629, 1 + 1j]
+        self.assert_function_values('arcsin', arcsin_inputs, arcsin_angles)
+        # rather than throwing an exception, numpy.arcsin gives nan
+        # self.assertTrue(numpy.isnan(calc.evaluator({}, {}, 'arcsin(-1.1)')))
+        # self.assertTrue(numpy.isnan(calc.evaluator({}, {}, 'arcsin(1.1)')))
+        # disabled for now because they are giving a runtime warning... :-/
+
+        # include those where the real part is between 0 and pi
+        arccos_inputs = ['1', '0.866', '0.809', '0.834-0.989*j']
+        arccos_angles = [0, 0.524, 0.628, 1 + 1j]
+        self.assert_function_values('arccos', arccos_inputs, arccos_angles)
+        # self.assertTrue(numpy.isnan(calc.evaluator({}, {}, 'arccos(-1.1)')))
+        # self.assertTrue(numpy.isnan(calc.evaluator({}, {}, 'arccos(1.1)')))
+
+        # has the same range as arcsin
+        arctan_inputs = ['-1', '0', '0.577', '0.727', '0.272 + 1.084*j']
+        arctan_angles = arcsin_angles
+        self.assert_function_values('arctan', arctan_inputs, arctan_angles)
+
+    def test_other_functions(self):
+        """Test the other functions provided in common/lib/calc/calc.py"""
+        # sqrt, log10, log2, ln, abs,
+        # fact, factorial
+
+        # test sqrt
+        self.assert_function_values('sqrt',
+                                    [0, 1, 2, 1024],  # -1
+                                    [0, 1, 1.414, 32])  # 1j
+        # sqrt(-1) is NAN not j (!!).
+
+        # test logs
+        self.assert_function_values('log10',
+                                    [0.1, 1, 3.162, 1000000, '1+j'],
+                                    [-1, 0, 0.5, 6, 0.151 + 0.341j])
+        self.assert_function_values('log2',
+                                    [0.5, 1, 1.414, 1024, '1+j'],
+                                    [-1, 0, 0.5, 10, 0.5 + 1.133j])
+        self.assert_function_values('ln',
+                                    [0.368, 1, 1.649, 2.718, 42, '1+j'],
+                                    [-1, 0, 0.5, 1, 3.738, 0.347 + 0.785j])
+
+        # test abs
+        self.assert_function_values('abs', [-1, 0, 1, 'j'], [1, 0, 1, 1])
+
+        # test factorial
+        fact_inputs = [0, 1, 3, 7]
+        fact_values = [1, 1, 6, 5040]
+        self.assert_function_values('fact', fact_inputs, fact_values)
+        self.assert_function_values('factorial', fact_inputs, fact_values)
+
+        self.assertRaises(ValueError, calc.evaluator, {}, {}, "fact(-1)")
+        self.assertRaises(ValueError, calc.evaluator, {}, {}, "fact(0.5)")
+        self.assertRaises(ValueError, calc.evaluator, {}, {}, "factorial(-1)")
+        self.assertRaises(ValueError, calc.evaluator, {}, {}, "factorial(0.5)")
+
+    def test_constants(self):
+        """Test the default constants provided in common/lib/calc/calc.py"""
+        # which are: j (complex number), e, pi, k, c, T, q
+
+        # ('expr', python value, tolerance (or None for exact))
+        default_variables = [('j', 1j, None),
+                             ('e', 2.7183, 1e-3),
+                             ('pi', 3.1416, 1e-3),
+                             # c = speed of light
+                             ('c', 2.998e8, 1e5),
+                             # 0 deg C = T Kelvin
+                             ('T', 298.15, 0.01),
+                             # note k = scipy.constants.k = 1.3806488e-23
+                             ('k', 1.3806488e-23, 1e-26),
+                             # note q = scipy.constants.e = 1.602176565e-19
+                             ('q', 1.602176565e-19, 1e-22)]
+        for (variable, value, tolerance) in default_variables:
+            fail_msg = "Failed on constant '{0}', not within bounds".format(
+                variable)
+            result = calc.evaluator({}, {}, variable)
+            if tolerance is None:
+                self.assertEqual(value, result, msg=fail_msg)
+            else:
+                self.assertAlmostEqual(value, result,
+                                        delta=tolerance, msg=fail_msg)
+
+    def test_complex_expression(self):
+        """We've only tried simple things so far, make sure it can handle a
+        more complexity than this."""
+
+        self.assertAlmostEqual(
+            calc.evaluator({}, {}, "(2^2+1.0)/sqrt(5e0)*5-1"),
+            10.180,
+            delta=1e-3)
+
+        self.assertAlmostEqual(
+            calc.evaluator({}, {}, "1+1/(1+1/(1+1/(1+1)))"),
+            1.6,
+            delta=1e-3)
+        self.assertAlmostEqual(
+            calc.evaluator({}, {}, "10||sin(7+5)"),
+            -0.567, delta=0.01)
+
+    def test_calc(self):
+        variables = {'R1': 2.0, 'R3': 4.0}
+        functions = {'sin': numpy.sin, 'cos': numpy.cos}
+
+        self.assertAlmostEqual(
+            calc.evaluator(variables, functions, "10||sin(7+5)"),
+            -0.567, delta=0.01)
+        self.assertEqual(calc.evaluator({'R1': 2.0, 'R3': 4.0}, {}, "13"), 13)
+        self.assertEqual(calc.evaluator(variables, functions, "13"), 13)
+        self.assertEqual(
+            calc.evaluator({
+                'a': 2.2997471478310274, 'k': 9, 'm': 8,
+                'x': 0.66009498411213041},
+                           {}, "5"),
+            5)
+        self.assertEqual(calc.evaluator(variables, functions, "R1*R3"), 8.0)
+        self.assertAlmostEqual(calc.evaluator(variables, functions, "sin(e)"), 0.41, delta=0.01)
+        self.assertAlmostEqual(calc.evaluator(variables, functions, "k*T/q"), 0.025, delta=1e-3)
+        self.assertAlmostEqual(calc.evaluator(variables, functions, "e^(j*pi)"), -1, delta=1e-5)
+
+        variables['t'] = 1.0
+        self.assertAlmostEqual(calc.evaluator(variables, functions, "t"), 1.0, delta=1e-5)
+        self.assertAlmostEqual(calc.evaluator(variables, functions, "T"), 1.0, delta=1e-5)
+        self.assertAlmostEqual(calc.evaluator(variables, functions, "t", cs=True), 1.0, delta=1e-5)
+        self.assertAlmostEqual(calc.evaluator(variables, functions, "T", cs=True), 298, delta=0.2)
+
+        self.assertRaises(calc.UndefinedVariable, calc.evaluator,
+                          {}, {}, "5+7 QWSEKO")
+
+        self.assertRaises(calc.UndefinedVariable, calc.evaluator,
+                          {'r1': 5}, {}, "r1+r2")
+
+        self.assertEqual(calc.evaluator(variables, functions, "r1*r3"), 8.0)
+
+        self.assertRaises(calc.UndefinedVariable, calc.evaluator,
+                          variables, functions, "r1*r3", cs=True)