diff --git a/docs/faq.md b/docs/faq.md index da443e33..1b6d8b6d 100644 --- a/docs/faq.md +++ b/docs/faq.md @@ -60,9 +60,10 @@ the rule. ## Why does googletest support `EXPECT_EQ(NULL, ptr)` and `ASSERT_EQ(NULL, ptr)` but not `EXPECT_NE(NULL, ptr)` and `ASSERT_NE(NULL, ptr)`? -First of all you can use `EXPECT_NE(nullptr, ptr)` and `ASSERT_NE(nullptr, -ptr)`. This is the preferred syntax in the style guide because nullptr does not -have the type problems that NULL does. Which is why NULL does not work. +First of all, you can use `nullptr` with each of these macros, e.g. +`EXPECT_EQ(ptr, nullptr)`, `EXPECT_NE(ptr, nullptr)`, `ASSERT_EQ(ptr, nullptr)`, +`ASSERT_NE(ptr, nullptr)`. This is the preferred syntax in the style guide +because `nullptr` does not have the type problems that `NULL` does. Due to some peculiarity of C++, it requires some non-trivial template meta programming tricks to support using `NULL` as an argument of the `EXPECT_XX()` @@ -70,22 +71,21 @@ and `ASSERT_XX()` macros. Therefore we only do it where it's most needed (otherwise we make the implementation of googletest harder to maintain and more error-prone than necessary). -The `EXPECT_EQ()` macro takes the *expected* value as its first argument and the -*actual* value as the second. It's reasonable that someone wants to write -`EXPECT_EQ(NULL, some_expression)`, and this indeed was requested several times. -Therefore we implemented it. +Historically, the `EXPECT_EQ()` macro took the *expected* value as its first +argument and the *actual* value as the second, though this argument order is now +discouraged. It was reasonable that someone wanted +to write `EXPECT_EQ(NULL, some_expression)`, and this indeed was requested +several times. Therefore we implemented it. -The need for `EXPECT_NE(NULL, ptr)` isn't nearly as strong. When the assertion +The need for `EXPECT_NE(NULL, ptr)` wasn't nearly as strong. When the assertion fails, you already know that `ptr` must be `NULL`, so it doesn't add any information to print `ptr` in this case. That means `EXPECT_TRUE(ptr != NULL)` works just as well. -If we were to support `EXPECT_NE(NULL, ptr)`, for consistency we'll have to -support `EXPECT_NE(ptr, NULL)` as well, as unlike `EXPECT_EQ`, we don't have a -convention on the order of the two arguments for `EXPECT_NE`. This means using -the template meta programming tricks twice in the implementation, making it even -harder to understand and maintain. We believe the benefit doesn't justify the -cost. +If we were to support `EXPECT_NE(NULL, ptr)`, for consistency we'd have to +support `EXPECT_NE(ptr, NULL)` as well. This means using the template meta +programming tricks twice in the implementation, making it even harder to +understand and maintain. We believe the benefit doesn't justify the cost. Finally, with the growth of the gMock matcher library, we are encouraging people to use the unified `EXPECT_THAT(value, matcher)` syntax more often in tests. One