Fix math.log to pass some failed tests

Now math.log with less than or equal to zero should raise ValueError
with "math domain error" message if `x` fit in f64

Lib/test/test_statistics.py

@@ -2133,8 +2133,6 @@ class TestGeometricMean(unittest.TestCase):
         self.assertTrue(math.isclose(small_gm, 36.0 * small))
         self.assertNotEqual(small_gm, 0.0)
 
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
     def test_error_cases(self):
         geometric_mean = statistics.geometric_mean
         StatisticsError = statistics.StatisticsError
@@ -2155,8 +2153,6 @@ class TestGeometricMean(unittest.TestCase):
         with self.assertRaises(TypeError):
             geometric_mean([10, 20, 60], 70)        # too many arguments
 
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
     def test_special_values(self):
         # Rules for special values are inherited from math.fsum()
         geometric_mean = statistics.geometric_mean

stdlib/src/math.rs

@@ -130,8 +130,18 @@ mod math {
     }
 
     #[pyfunction]
-    fn log(x: ArgIntoFloat, base: OptionalArg<ArgIntoFloat>) -> f64 {
-        base.map_or_else(|| x.to_f64().ln(), |base| x.to_f64().log(base.to_f64()))
+    fn log(x: ArgIntoFloat, base: OptionalArg<ArgIntoFloat>, vm: &VirtualMachine) -> PyResult<f64> {
+        let x = x.to_f64();
+        base.map_or_else(
+            || {
+                if x.is_nan() || x > 0.0_f64 {
+                    Ok(x.ln())
+                } else {
+                    Err(vm.new_value_error("math domain error".to_owned()))
+                }
+            },
+            |base| Ok(x.log(base.to_f64())),
+        )
     }
 
     #[pyfunction]