[RFC v2 12/12] kunit: mock: implement nice, strict and naggy mock distinctions

From: Daniel Latypov
Date: Mon Oct 12 2020 - 18:22:10 EST

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From: Brendan Higgins <brendanhiggins@xxxxxxxxxx>

Nice mocks only fail when there is an expectation on a method, but none
match a given call. Strict mocks only pass when there is a matching
expectation for every call. Naggy mocks have the same pass/fail behavior
as nice, but report a warning in any case a strict mock would fail.

Signed-off-by: Felix Guo <felixguoxiuping@xxxxxxxxx>
Signed-off-by: Brendan Higgins <brendanhiggins@xxxxxxxxxx>
Signed-off-by: Daniel Latypov <dlatypov@xxxxxxxxxx>
---
include/kunit/mock.h | 63 ++++++++++++++++
lib/kunit/mock-test.c | 171 ++++++++++++++++++++++++++++++++++++++++++
lib/kunit/mock.c | 10 ++-
3 files changed, 242 insertions(+), 2 deletions(-)

diff --git a/include/kunit/mock.h b/include/kunit/mock.h
index df99ae5ac721..12e70a3f82c5 100644
--- a/include/kunit/mock.h
+++ b/include/kunit/mock.h
@@ -95,10 +95,17 @@ struct mock_method {
struct list_head expectations;
};

+enum mock_type {
+ MOCK_TYPE_NICE,
+ MOCK_TYPE_NAGGY,
+ MOCK_TYPE_STRICT
+};
+
struct mock {
struct kunit_post_condition parent;
struct kunit *test;
struct list_head methods;
+ enum mock_type type;
/* TODO(brendanhiggins@xxxxxxxxxx): add locking to do_expect. */
const void *(*do_expect)(struct mock *mock,
const char *method_name,
@@ -108,6 +115,8 @@ struct mock {
int len);
};

+#define DEFAULT_MOCK_TYPE MOCK_TYPE_NAGGY
+
void mock_init_ctrl(struct kunit *test, struct mock *mock);

void mock_validate_expectations(struct mock *mock);
@@ -125,6 +134,60 @@ struct mock_expectation *mock_add_matcher(struct mock *mock,

#define MOCK(name) name##_mock

+/**
+ * STRICT_MOCK() - sets the mock to be strict and returns the mock
+ * @mock: the mock
+ *
+ * For an example, see ``The Nice, the Strict, and the Naggy`` under
+ * ``Using KUnit``.
+ */
+#define STRICT_MOCK(mock) \
+({ \
+ mock_get_ctrl(mock)->type = MOCK_TYPE_STRICT; \
+ mock; \
+})
+
+static inline bool is_strict_mock(struct mock *mock)
+{
+ return mock->type == MOCK_TYPE_STRICT;
+}
+
+/**
+ * NICE_MOCK() - sets the mock to be nice and returns the mock
+ * @mock: the mock
+ *
+ * For an example, see ``The Nice, the Strict, and the Naggy`` under
+ * ``Using KUnit``.
+ */
+#define NICE_MOCK(mock) \
+({ \
+ mock_get_ctrl(mock)->type = MOCK_TYPE_NICE; \
+ mock; \
+})
+
+static inline bool is_nice_mock(struct mock *mock)
+{
+ return mock->type == MOCK_TYPE_NICE;
+}
+
+/**
+ * NAGGY_MOCK() - sets the mock to be naggy and returns the mock
+ * @mock: the mock
+ *
+ * For an example, see ``The Nice, the Strict, and the Naggy`` under
+ * ``Using KUnit``.
+ */
+#define NAGGY_MOCK(mock) \
+({ \
+ mock_get_ctrl(mock)->type = MOCK_TYPE_NAGGY; \
+ mock; \
+})
+
+static inline bool is_naggy_mock(struct mock *mock)
+{
+ return mock->type == MOCK_TYPE_NAGGY;
+}
+
/**
* KUNIT_EXPECT_CALL() - Declares a *call expectation* on a mock function.
* @expectation_call: a mocked method or function with parameters replaced with
diff --git a/lib/kunit/mock-test.c b/lib/kunit/mock-test.c
index df0969b43ade..1c2aa2aa9c1b 100644
--- a/lib/kunit/mock-test.c
+++ b/lib/kunit/mock-test.c
@@ -243,6 +243,50 @@ static void mock_test_do_expect_default_return(struct kunit *test)
KUNIT_EXPECT_EQ(test, 0, expectation->times_called);
}

+/**
+ * DOC: Testing the failure condition of different mock types.
+ *
+ * The following tests will test the behaviour of expectations under different
+ * conditions. For example, what happens when an expectation:
+ * - is not satisfied at the end of the test
+ * - is fulfilled but the expected function is called again
+ * - a function is called without expectations set on it
+ *
+ * For each of these conditions, there may be variations between the different
+ * types of mocks: nice mocks, naggy mocks (the default) and strict mocks.
+ *
+ * More information about these mocks can be found in the kernel documentation
+ * under Documentation/test/api/class-and-function-mocking
+ */
+
+/* Method called on strict mock with no expectations will fail */
+static void mock_test_strict_no_expectations_will_fail(struct kunit *test)
+{
+ struct mock_test_context *ctx = test->priv;
+ struct kunit *failing_test = ctx->failing_test;
+ struct mock *mock = ctx->mock;
+ int param0 = 5, param1 = -5;
+ static const char * const two_param_types[] = {"int", "int"};
+ const void *two_params[] = {&param0, &param1};
+
+ mock->type = MOCK_TYPE_STRICT;
+
+ mock_set_default_action(mock,
+ "add",
+ mock_add,
+ kunit_int_return(failing_test, -4));
+
+ mock->do_expect(mock,
+ "add",
+ mock_add,
+ two_param_types,
+ two_params,
+ ARRAY_SIZE(two_params));
+ mock_validate_expectations(mock);
+
+ KUNIT_EXPECT_FALSE(test, failing_test->success);
+}
+
/*
* Method called on naggy mock with no expectations will not fail, but will show
* a warning message
@@ -257,6 +301,8 @@ static void mock_test_naggy_no_expectations_no_fail(struct kunit *test)
static const char * const two_param_types[] = {"int", "int"};
const void *two_params[] = {&param0, &param1};

+ mock->type = MOCK_TYPE_NAGGY;
+
mock_set_default_action(mock,
"add",
real_add,
@@ -282,6 +328,77 @@ static void mock_test_naggy_no_expectations_no_fail(struct kunit *test)
KUNIT_EXPECT_FALSE(test, failing_test->success);
}

+/* Method called on nice mock with no expectations will do nothing. */
+static void mock_test_nice_no_expectations_do_nothing(struct kunit *test)
+{
+ struct mock_test_context *ctx = test->priv;
+ struct kunit *failing_test = ctx->failing_test;
+ struct mock *mock = ctx->mock;
+ int param0 = 5, param1 = -5;
+ static const char * const two_param_types[] = {"int", "int"};
+ const void *two_params[] = {&param0, &param1};
+
+ mock->type = MOCK_TYPE_NICE;
+
+ mock->do_expect(mock,
+ "add",
+ mock_add,
+ two_param_types,
+ two_params,
+ ARRAY_SIZE(two_params));
+ mock_validate_expectations(mock);
+
+ KUNIT_EXPECT_TRUE(test, failing_test->success);
+}
+
+/* Test that method called on a mock (of any type) with no matching expectations
+ * will fail test and print all the tried expectations.
+ */
+static void
+run_method_called_but_no_matching_expectation_test(struct kunit *test,
+ enum mock_type mock_type)
+{
+ struct mock_test_context *ctx = test->priv;
+ struct kunit *failing_test = ctx->failing_test;
+ struct mock *mock = ctx->mock;
+ int param0 = 5, param1 = -5;
+ static const char * const two_param_types[] = {"int", "int"};
+ const void *two_params[] = {&param0, &param1};
+ struct mock_param_matcher *two_matchers[] = {
+ kunit_int_eq(failing_test, 100),
+ kunit_int_eq(failing_test, 100)
+ };
+
+ mock_add_matcher(mock, "add", mock_add, two_matchers,
+ ARRAY_SIZE(two_matchers));
+
+ mock->type = mock_type;
+
+ mock->do_expect(mock, "add", mock_add, two_param_types, two_params,
+ ARRAY_SIZE(two_params));
+
+ /* Even nice mocks should fail if there's an unmet expectation. */
+ KUNIT_EXPECT_FALSE(test, failing_test->success);
+}
+
+static void mock_test_naggy_no_matching_expectations_fail(struct kunit *test)
+{
+ run_method_called_but_no_matching_expectation_test(test,
+ MOCK_TYPE_NAGGY);
+}
+
+static void mock_test_strict_no_matching_expectations_fail(struct kunit *test)
+{
+ run_method_called_but_no_matching_expectation_test(test,
+ MOCK_TYPE_STRICT);
+}
+
+static void mock_test_nice_no_matching_expectations_fail(struct kunit *test)
+{
+ run_method_called_but_no_matching_expectation_test(test,
+ MOCK_TYPE_NICE);
+}
+
static void mock_test_mock_validate_expectations(struct kunit *test)
{
struct mock_test_context *ctx = test->priv;
@@ -309,6 +426,54 @@ static void mock_test_mock_validate_expectations(struct kunit *test)
KUNIT_EXPECT_FALSE(test, failing_test->success);
}

+static void mock_test_validate_clears_expectations(struct kunit *test)
+{
+ struct mock_test_context *ctx = test->priv;
+ struct kunit *failing_test = ctx->failing_test;
+ struct mock *mock = ctx->mock;
+ struct mock_param_matcher *matchers[] = {
+ kunit_int_eq(failing_test, 5),
+ kunit_int_eq(failing_test, -4)
+ };
+ int param0 = 5, param1 = -4;
+ static const char * const two_param_types[] = {"int", "int"};
+ const void *two_params[] = {&param0, &param1};
+
+ struct mock_expectation *expectation;
+
+ mock->type = MOCK_TYPE_STRICT;
+
+ /* Add an arbitrary matcher for 0 calls */
+ expectation = mock_add_matcher(mock, "add", mock_add,
+ matchers, ARRAY_SIZE(matchers));
+ expectation->times_called = 0;
+ expectation->min_calls_expected = 0;
+ expectation->max_calls_expected = 0;
+
+ /* Should have 0 calls and should clear the previous expectation */
+ mock_validate_expectations(mock);
+
+ /* Add a new matcher for 1 call */
+ expectation = mock_add_matcher(mock, "add", mock_add,
+ matchers, ARRAY_SIZE(matchers));
+ expectation->times_called = 0;
+ expectation->min_calls_expected = 1;
+ expectation->max_calls_expected = 1;
+
+ /* Satisfy previous matcher */
+ mock->do_expect(mock, "add", mock_add, two_param_types, two_params,
+ ARRAY_SIZE(two_params));
+
+ /*
+ * Validate previous satisfy; if we didn't clear the previous
+ * expectation, it would fail the mock_test.
+ */
+ mock_validate_expectations(mock);
+
+ /* If all goes well, shouldn't fail the test. */
+ KUNIT_EXPECT_TRUE(test, failing_test->success);
+}
+
static int mock_test_init(struct kunit *test)
{
struct mock_test_context *ctx;
@@ -346,7 +511,13 @@ static struct kunit_case mock_test_cases[] = {
KUNIT_CASE(mock_test_failed_expect_call_fails_test),
KUNIT_CASE(mock_test_do_expect_default_return),
KUNIT_CASE(mock_test_mock_validate_expectations),
+ KUNIT_CASE(mock_test_strict_no_expectations_will_fail),
KUNIT_CASE(mock_test_naggy_no_expectations_no_fail),
+ KUNIT_CASE(mock_test_nice_no_expectations_do_nothing),
+ KUNIT_CASE(mock_test_strict_no_matching_expectations_fail),
+ KUNIT_CASE(mock_test_naggy_no_matching_expectations_fail),
+ KUNIT_CASE(mock_test_nice_no_matching_expectations_fail),
+ KUNIT_CASE(mock_test_validate_clears_expectations),
{}
};

diff --git a/lib/kunit/mock.c b/lib/kunit/mock.c
index 12fb88899451..f1fa7a5b9dd4 100644
--- a/lib/kunit/mock.c
+++ b/lib/kunit/mock.c
@@ -85,6 +85,7 @@ void mock_init_ctrl(struct kunit *test, struct mock *mock)
mock->test = test;
INIT_LIST_HEAD(&mock->methods);
mock->do_expect = mock_do_expect;
+ mock->type = DEFAULT_MOCK_TYPE;
mock->parent.validate = mock_validate_wrapper;
list_add_tail(&mock->parent.node, &test->post_conditions);
}
@@ -283,7 +284,12 @@ static struct mock_expectation *mock_apply_expectations(
mock_add_method_expectation_error(test, stream,
"Method was called with no expectations declared: ",
mock, method, type_names, params, len);
- kunit_stream_commit(stream);
+ if (is_strict_mock(mock))
+ fail_and_flush(test, stream);
+ else if (is_naggy_mock(mock))
+ kunit_stream_commit(stream);
+ else
+ kunit_stream_clear(stream);
return NULL;
}

@@ -313,7 +319,7 @@ static struct mock_expectation *mock_apply_expectations(
}
}

- if (expectations_all_saturated) {
+ if (expectations_all_saturated && !is_nice_mock(mock)) {
mock_add_method_expectation_error(test, stream,
"Method was called with fully saturated expectations: ",
mock, method, type_names, params, len);
--
2.28.0.1011.ga647a8990f-goog

Next message: Daniel Latypov: "[RFC v2 11/12] kunit: mock: add struct param matcher"
Previous message: Daniel Latypov: "[RFC v2 08/12] kunit: mock: add basic matchers and actions"
In reply to: Daniel Latypov: "[RFC v2 08/12] kunit: mock: add basic matchers and actions"
Next in thread: Daniel Latypov: "[RFC v2 11/12] kunit: mock: add struct param matcher"
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