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base / scoped_observation_unittest.cc [blame]
// Copyright 2020 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "base/scoped_observation.h"
#include "base/containers/contains.h"
#include "base/memory/raw_ptr.h"
#include "base/ranges/algorithm.h"
#include "base/scoped_observation_traits.h"
#include "testing/gtest/include/gtest/gtest.h"
namespace base {
namespace {
class TestSourceObserver {
public:
virtual ~TestSourceObserver() = default;
};
class TestSource {
public:
void AddObserver(TestSourceObserver* observer);
void RemoveObserver(TestSourceObserver* observer);
bool HasObserver(TestSourceObserver* observer) const;
size_t num_observers() const { return observers_.size(); }
private:
std::vector<raw_ptr<TestSourceObserver, VectorExperimental>> observers_;
};
void TestSource::AddObserver(TestSourceObserver* observer) {
observers_.push_back(observer);
}
void TestSource::RemoveObserver(TestSourceObserver* observer) {
auto it = base::ranges::find(observers_, observer);
EXPECT_TRUE(it != observers_.end());
observers_.erase(it);
}
bool TestSource::HasObserver(TestSourceObserver* observer) const {
return base::Contains(observers_, observer);
}
using TestScopedObservation = ScopedObservation<TestSource, TestSourceObserver>;
} // namespace
TEST(ScopedObservationTest, RemovesObservationOnDestruction) {
TestSource s1;
{
TestSourceObserver o1;
TestScopedObservation obs(&o1);
const TestScopedObservation& cobs = obs;
EXPECT_EQ(0u, s1.num_observers());
EXPECT_FALSE(s1.HasObserver(&o1));
EXPECT_EQ(obs.GetSource(), nullptr);
EXPECT_EQ(cobs.GetSource(), nullptr);
obs.Observe(&s1);
EXPECT_EQ(1u, s1.num_observers());
EXPECT_TRUE(s1.HasObserver(&o1));
TestSource* const got_source = obs.GetSource();
EXPECT_EQ(got_source, &s1);
EXPECT_EQ(cobs.GetSource(), &s1);
}
// Test that the observation is removed when it goes out of scope.
EXPECT_EQ(0u, s1.num_observers());
}
TEST(ScopedObservationTest, Reset) {
TestSource s1;
TestSourceObserver o1;
TestScopedObservation obs(&o1);
const TestScopedObservation& cobs = obs;
EXPECT_EQ(0u, s1.num_observers());
EXPECT_EQ(obs.GetSource(), nullptr);
EXPECT_EQ(cobs.GetSource(), nullptr);
obs.Reset();
EXPECT_EQ(obs.GetSource(), nullptr);
EXPECT_EQ(cobs.GetSource(), nullptr);
obs.Observe(&s1);
EXPECT_EQ(1u, s1.num_observers());
EXPECT_TRUE(s1.HasObserver(&o1));
EXPECT_EQ(obs.GetSource(), &s1);
EXPECT_EQ(cobs.GetSource(), &s1);
obs.Reset();
EXPECT_EQ(0u, s1.num_observers());
EXPECT_EQ(obs.GetSource(), nullptr);
EXPECT_EQ(cobs.GetSource(), nullptr);
// Safe to call with no observation.
obs.Reset();
EXPECT_EQ(0u, s1.num_observers());
EXPECT_EQ(obs.GetSource(), nullptr);
EXPECT_EQ(cobs.GetSource(), nullptr);
}
TEST(ScopedObservationTest, IsObserving) {
TestSource s1;
TestSourceObserver o1;
TestScopedObservation obs(&o1);
const TestScopedObservation& cobs = obs;
EXPECT_FALSE(cobs.IsObserving());
EXPECT_EQ(obs.GetSource(), nullptr);
EXPECT_EQ(cobs.GetSource(), nullptr);
obs.Observe(&s1);
EXPECT_TRUE(cobs.IsObserving());
EXPECT_EQ(obs.GetSource(), &s1);
EXPECT_EQ(cobs.GetSource(), &s1);
obs.Reset();
EXPECT_FALSE(cobs.IsObserving());
EXPECT_EQ(obs.GetSource(), nullptr);
EXPECT_EQ(cobs.GetSource(), nullptr);
}
TEST(ScopedObservationTest, IsObservingSource) {
TestSource s1;
TestSource s2;
TestSourceObserver o1;
TestScopedObservation obs(&o1);
const TestScopedObservation& cobs = obs;
EXPECT_FALSE(cobs.IsObservingSource(&s1));
EXPECT_FALSE(cobs.IsObservingSource(&s2));
EXPECT_EQ(obs.GetSource(), nullptr);
EXPECT_EQ(cobs.GetSource(), nullptr);
obs.Observe(&s1);
EXPECT_TRUE(cobs.IsObservingSource(&s1));
EXPECT_FALSE(cobs.IsObservingSource(&s2));
EXPECT_EQ(obs.GetSource(), &s1);
EXPECT_EQ(cobs.GetSource(), &s1);
obs.Reset();
EXPECT_FALSE(cobs.IsObservingSource(&s1));
EXPECT_FALSE(cobs.IsObservingSource(&s2));
EXPECT_EQ(obs.GetSource(), nullptr);
EXPECT_EQ(cobs.GetSource(), nullptr);
}
namespace {
// A test source with oddly named Add/Remove functions.
class TestSourceWithNonDefaultNames {
public:
void AddFoo(TestSourceObserver* observer) { impl_.AddObserver(observer); }
void RemoveFoo(TestSourceObserver* observer) {
impl_.RemoveObserver(observer);
}
const TestSource& impl() const { return impl_; }
private:
TestSource impl_;
};
using TestScopedObservationWithNonDefaultNames =
ScopedObservation<TestSourceWithNonDefaultNames, TestSourceObserver>;
} // namespace
template <>
struct ScopedObservationTraits<TestSourceWithNonDefaultNames,
TestSourceObserver> {
static void AddObserver(TestSourceWithNonDefaultNames* source,
TestSourceObserver* observer) {
source->AddFoo(observer);
}
static void RemoveObserver(TestSourceWithNonDefaultNames* source,
TestSourceObserver* observer) {
source->RemoveFoo(observer);
}
};
TEST(ScopedObservationTest, NonDefaultNames) {
TestSourceWithNonDefaultNames s1;
TestSourceObserver o1;
EXPECT_EQ(0u, s1.impl().num_observers());
{
TestScopedObservationWithNonDefaultNames obs(&o1);
obs.Observe(&s1);
EXPECT_EQ(1u, s1.impl().num_observers());
EXPECT_TRUE(s1.impl().HasObserver(&o1));
}
EXPECT_EQ(0u, s1.impl().num_observers());
}
namespace {
// A forward-declared test source.
class TestSourceFwd;
class ObservationHolder : public TestSourceObserver {
public:
// Declared but not defined since TestSourceFwd is not yet defined.
explicit ObservationHolder(TestSourceFwd* source);
private:
// ScopedObservation<> is instantiated with a forward-declared parameter.
ScopedObservation<TestSourceFwd, TestSourceObserver> obs_{this};
};
// TestSourceFwd gets an actual definition!
class TestSourceFwd : public TestSource {};
// Calling ScopedObservation::Observe() requires an actual definition rather
// than just a forward declaration; make sure it compiles now that there is a
// definition.
ObservationHolder::ObservationHolder(TestSourceFwd* source) {
obs_.Observe(source);
}
} // namespace
TEST(ScopedObservationTest, ForwardDeclaredSource) {
TestSourceFwd s;
ASSERT_EQ(s.num_observers(), 0U);
{
ObservationHolder o(&s);
ASSERT_EQ(s.num_observers(), 1U);
}
ASSERT_EQ(s.num_observers(), 0U);
}
namespace {
class TestSourceWithNonDefaultNamesFwd;
class ObservationWithNonDefaultNamesHolder : public TestSourceObserver {
public:
// Declared but not defined since TestSourceWithNonDefaultNamesFwd is not yet
// defined.
explicit ObservationWithNonDefaultNamesHolder(
TestSourceWithNonDefaultNamesFwd* source);
private:
// ScopedObservation<> is instantiated with a forward-declared parameter.
ScopedObservation<TestSourceWithNonDefaultNamesFwd, TestSourceObserver> obs_{
this};
};
// TestSourceWithNonDefaultNamesFwd gets an actual definition!
class TestSourceWithNonDefaultNamesFwd : public TestSourceWithNonDefaultNames {
};
} // namespace
// Now we define the corresponding traits. ScopedObservationTraits
// specializations must be defined in base::, since that is where the primary
// template definition lives.
template <>
struct ScopedObservationTraits<TestSourceWithNonDefaultNamesFwd,
TestSourceObserver> {
static void AddObserver(TestSourceWithNonDefaultNamesFwd* source,
TestSourceObserver* observer) {
source->AddFoo(observer);
}
static void RemoveObserver(TestSourceWithNonDefaultNamesFwd* source,
TestSourceObserver* observer) {
source->RemoveFoo(observer);
}
};
namespace {
// Calling ScopedObservation::Observe() requires an actual definition rather
// than just a forward declaration; make sure it compiles now that there is
// a definition.
ObservationWithNonDefaultNamesHolder::ObservationWithNonDefaultNamesHolder(
TestSourceWithNonDefaultNamesFwd* source) {
obs_.Observe(source);
}
} // namespace
TEST(ScopedObservationTest, ForwardDeclaredSourceWithNonDefaultNames) {
TestSourceWithNonDefaultNamesFwd s;
ASSERT_EQ(s.impl().num_observers(), 0U);
{
ObservationWithNonDefaultNamesHolder o(&s);
ASSERT_EQ(s.impl().num_observers(), 1U);
}
ASSERT_EQ(s.impl().num_observers(), 0U);
}
} // namespace base