Merge pull request RustPython#4152 from jopemachine/fix-math-pow

Fix edge case of `math.pow(0.0, -inf)`, `math.pow(-0.0, -inf)`

Author: youknowone

Lib/test/test_math.py

@@ -1227,8 +1227,6 @@ def testmodf(name, result, expected):
         self.assertTrue(math.isnan(modf_nan[0]))
         self.assertTrue(math.isnan(modf_nan[1]))
 
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
     def testPow(self):
         self.assertRaises(TypeError, math.pow)
         self.ftest('pow(0,1)', math.pow(0,1), 0)

stdlib/src/math.rs

@@ -184,7 +184,7 @@ mod math {
             return Err(vm.new_value_error("math domain error".to_owned()));
         }
 
-        if x == 0.0 && y < 0.0 {
+        if x == 0.0 && y < 0.0 && y != f64::NEG_INFINITY {
             return Err(vm.new_value_error("math domain error".to_owned()));
         }