added tests for __cause__/InnerException #893 #1098

src/embed_tests/TestPythonException.cs

@@ -55,6 +55,36 @@ public void TestPythonErrorTypeName()
             }
         }
 
+        [Test]
+        public void TestNestedExceptions()
+        {
+            try
+            {
+                PythonEngine.Exec(@"
+try:
+  raise Exception('inner')
+except Exception as ex:
+  raise Exception('outer') from ex
+");
+            }
+            catch (PythonException ex)
+            {
+                Assert.That(ex.InnerException, Is.InstanceOf<PythonException>());
+                Assert.That(ex.InnerException.Message, Is.EqualTo("Exception : inner"));
+            }
+        }
+
+        [Test]
+        public void InnerIsEmptyWithNoCause()
+        {
+            var list = new PyList();
+            PyObject foo = null;
+
+            var ex = Assert.Throws<PythonException>(() => foo = list[0]);
+
+            Assert.IsNull(ex.InnerException);
+        }
+
         [Test]
         public void TestPythonExceptionFormat()
         {