TST: Move rate tests into own class

Author: Kai-Striega

numpy_financial/tests/test_financial.py

@@ -13,33 +13,6 @@
 
 
 class TestFinancial(object):
-    def test_rate(self):
-        assert_almost_equal(npf.rate(10, 0, -3500, 10000), 0.1107, 4)
-
-    @pytest.mark.parametrize('number_type', [Decimal, float])
-    @pytest.mark.parametrize('when', [0, 1, 'end', 'begin'])
-    def test_rate_with_infeasible_solution(self, number_type, when):
-        """
-        Test when no feasible rate can be found.
-
-        Rate will return NaN, if the Newton Raphson method cannot find a
-        feasible rate within the required tolerance or number of iterations.
-        This can occur if both `pmt` and `pv` have the same sign, as it is
-        impossible to repay a loan by making further withdrawls.
-        """
-        result = npf.rate(number_type(12.0),
-                          number_type(400.0),
-                          number_type(10000.0),
-                          number_type(5000.0),
-                          when=when)
-        is_nan = Decimal.is_nan if number_type == Decimal else numpy.isnan
-        assert is_nan(result)
-
-    def test_rate_decimal(self):
-        rate = npf.rate(Decimal('10'), Decimal('0'), Decimal('-3500'),
-                        Decimal('10000'))
-        assert_equal(Decimal('0.1106908537142689284704528100'), rate)
-
     def test_pv(self):
         assert_almost_equal(npf.pv(0.07, 20, 12000, 0), -127128.17, 2)
 
@@ -120,6 +93,35 @@ def test_decimal_with_when(self):
                             Decimal('0'), 'end'))
 
 
+class TestRate:
+    def test_rate(self):
+        assert_almost_equal(npf.rate(10, 0, -3500, 10000), 0.1107, 4)
+
+    @pytest.mark.parametrize('number_type', [Decimal, float])
+    @pytest.mark.parametrize('when', [0, 1, 'end', 'begin'])
+    def test_rate_with_infeasible_solution(self, number_type, when):
+        """
+        Test when no feasible rate can be found.
+
+        Rate will return NaN, if the Newton Raphson method cannot find a
+        feasible rate within the required tolerance or number of iterations.
+        This can occur if both `pmt` and `pv` have the same sign, as it is
+        impossible to repay a loan by making further withdrawls.
+        """
+        result = npf.rate(number_type(12.0),
+                          number_type(400.0),
+                          number_type(10000.0),
+                          number_type(5000.0),
+                          when=when)
+        is_nan = Decimal.is_nan if number_type == Decimal else numpy.isnan
+        assert is_nan(result)
+
+    def test_rate_decimal(self):
+        rate = npf.rate(Decimal('10'), Decimal('0'), Decimal('-3500'),
+                        Decimal('10000'))
+        assert_equal(Decimal('0.1106908537142689284704528100'), rate)
+
+
 class TestNpv:
     def test_npv(self):
         assert_almost_equal(