hwmonio: Add injection point to test internal behavior
With the complexities of the various behaviors within the read() method
of HwmonIO, introduce an injection point for testing. There is a
default available, and therefore this is a surgical change that only
impacts future tests.
Signed-off-by: Patrick Venture <venture@google.com>
Change-Id: I1ead56c7fe1a2f87ebf316488e68f435a41c9d19
diff --git a/hwmonio.cpp b/hwmonio.cpp
index 9142c18..82d1a9d 100644
--- a/hwmonio.cpp
+++ b/hwmonio.cpp
@@ -25,6 +25,40 @@
namespace hwmonio
{
+int64_t FileSystem::read(const std::string& path) const
+{
+ int64_t val;
+ std::ifstream ifs;
+ ifs.exceptions(std::ifstream::failbit | std::ifstream::badbit |
+ std::ifstream::eofbit);
+
+ errno = 0;
+ if (!ifs.is_open())
+ ifs.open(path);
+ ifs.clear();
+ ifs.seekg(0);
+ ifs >> val;
+
+ return val;
+}
+
+void FileSystem::write(const std::string& path, uint32_t value) const
+{
+ std::ofstream ofs;
+ ofs.exceptions(std::ofstream::failbit | std::ofstream::badbit |
+ std::ofstream::eofbit);
+
+ errno = 0;
+ if (!ofs.is_open())
+ ofs.open(path);
+ ofs.clear();
+ ofs.seekp(0);
+ ofs << value;
+ ofs.flush();
+}
+
+FileSystem fileSystemImpl;
+
static constexpr auto retryableErrors = {
/*
* Retry on bus or device errors or timeouts in case
@@ -71,7 +105,8 @@
EMSGSIZE,
};
-HwmonIO::HwmonIO(const std::string& path) : _p(path)
+HwmonIO::HwmonIO(const std::string& path, const FileSystemInterface* intf) :
+ _p(path), _intf(intf)
{
}
@@ -80,22 +115,13 @@
std::chrono::milliseconds delay) const
{
int64_t val;
- std::ifstream ifs;
auto fullPath = sysfs::make_sysfs_path(_p, type, id, sensor);
- ifs.exceptions(std::ifstream::failbit | std::ifstream::badbit |
- std::ifstream::eofbit);
-
while (true)
{
try
{
- errno = 0;
- if (!ifs.is_open())
- ifs.open(fullPath);
- ifs.clear();
- ifs.seekg(0);
- ifs >> val;
+ val = _intf->read(fullPath);
}
catch (const std::exception& e)
{
@@ -148,12 +174,8 @@
size_t retries, std::chrono::milliseconds delay) const
{
- std::ofstream ofs;
auto fullPath = sysfs::make_sysfs_path(_p, type, id, sensor);
- ofs.exceptions(std::ofstream::failbit | std::ofstream::badbit |
- std::ofstream::eofbit);
-
// See comments in the read method for an explanation of the odd exception
// handling behavior here.
@@ -161,13 +183,7 @@
{
try
{
- errno = 0;
- if (!ofs.is_open())
- ofs.open(fullPath);
- ofs.clear();
- ofs.seekp(0);
- ofs << val;
- ofs.flush();
+ _intf->write(fullPath, val);
}
catch (const std::exception& e)
{
diff --git a/hwmonio.hpp b/hwmonio.hpp
index b0b8617..ff18204 100644
--- a/hwmonio.hpp
+++ b/hwmonio.hpp
@@ -9,6 +9,28 @@
static constexpr auto retries = 10;
static constexpr auto delay = std::chrono::milliseconds{100};
+/** @class FileSystemInterface
+ * @brief Abstract base class allowing testing of HwmonIO.
+ *
+ * This is used to provide testing of behaviors within HwmonIO.
+ */
+class FileSystemInterface
+{
+ public:
+ virtual ~FileSystemInterface() = default;
+ virtual int64_t read(const std::string& path) const = 0;
+ virtual void write(const std::string& path, uint32_t value) const = 0;
+};
+
+class FileSystem : public FileSystemInterface
+{
+ public:
+ int64_t read(const std::string& path) const override;
+ void write(const std::string& path, uint32_t value) const override;
+};
+
+extern FileSystem fileSystemImpl;
+
/** @class HwmonIOInterface
* @brief Abstract base class defining a HwmonIOInterface.
*
@@ -56,7 +78,8 @@
* @param[in] path - hwmon instance root - eg:
* /sys/class/hwmon/hwmon<N>
*/
- explicit HwmonIO(const std::string& path);
+ explicit HwmonIO(const std::string& path,
+ const FileSystemInterface* intf = &fileSystemImpl);
/** @brief Perform formatted hwmon sysfs read.
*
@@ -108,6 +131,7 @@
private:
std::string _p;
+ const FileSystemInterface* _intf;
};
} // namespace hwmonio
diff --git a/test/Makefile.am b/test/Makefile.am
index 37aa977..016409f 100644
--- a/test/Makefile.am
+++ b/test/Makefile.am
@@ -21,7 +21,7 @@
$(CODE_COVERAGE_LIBS)
# Run all 'check' test programs
-check_PROGRAMS = hwmon_unittest fanpwm_unittest sensor_unittest
+check_PROGRAMS = hwmon_unittest fanpwm_unittest sensor_unittest hwmonio_default_unittest
TESTS = $(check_PROGRAMS)
hwmon_unittest_SOURCES = hwmon_unittest.cpp
@@ -42,3 +42,6 @@
$(top_builddir)/hwmon.o \
env.o \
gpio.o
+
+hwmonio_default_unittest_SOURCES = hwmonio_default_unittest.cpp
+hwmonio_default_unittest_LDADD = $(top_builddir)/hwmonio.o
diff --git a/test/filesystem_mock.hpp b/test/filesystem_mock.hpp
new file mode 100644
index 0000000..9d24d3c
--- /dev/null
+++ b/test/filesystem_mock.hpp
@@ -0,0 +1,19 @@
+#pragma once
+
+#include "hwmonio.hpp"
+
+#include <string>
+
+#include <gmock/gmock.h>
+
+namespace hwmonio
+{
+
+class FileSystemMock : public FileSystemInterface
+{
+ public:
+ MOCK_CONST_METHOD1(read, int64_t(const std::string&));
+ MOCK_CONST_METHOD2(write, void(const std::string&, uint32_t));
+};
+
+} // namespace hwmonio
diff --git a/test/hwmonio_default_unittest.cpp b/test/hwmonio_default_unittest.cpp
new file mode 100644
index 0000000..233bf56
--- /dev/null
+++ b/test/hwmonio_default_unittest.cpp
@@ -0,0 +1,58 @@
+#include "filesystem_mock.hpp"
+#include "hwmonio.hpp"
+
+#include <chrono>
+#include <string>
+
+#include <gmock/gmock.h>
+#include <gtest/gtest.h>
+
+namespace hwmonio
+{
+namespace
+{
+
+using ::testing::_;
+using ::testing::Return;
+
+class HwmonIOTest : public ::testing::Test
+{
+ protected:
+ HwmonIOTest() : _hwmonio(_path, &_mock)
+ {
+ }
+
+ const int64_t _value = 12;
+ const std::string _path = "abcd";
+ const std::string _type = "fan";
+ const std::string _id = "a";
+ const std::string _sensor = "1";
+ const size_t _retries = 1;
+ const std::chrono::milliseconds _delay = std::chrono::milliseconds{10};
+
+ FileSystemMock _mock;
+ HwmonIO _hwmonio;
+};
+
+TEST_F(HwmonIOTest, ReadReturnsValue)
+{
+ EXPECT_CALL(_mock, read(_)).WillOnce(Return(_value));
+ EXPECT_THAT(_hwmonio.read(_type, _id, _sensor, _retries, _delay), _value);
+}
+
+int64_t SetErrnoExcept(const std::string&)
+{
+ errno = ETIMEDOUT;
+ throw std::runtime_error("bad times");
+}
+
+TEST_F(HwmonIOTest, ReadExceptsRetryable)
+{
+ EXPECT_CALL(_mock, read(_))
+ .WillOnce(&SetErrnoExcept)
+ .WillOnce(Return(_value));
+ EXPECT_THAT(_hwmonio.read(_type, _id, _sensor, _retries, _delay), _value);
+}
+
+} // namespace
+} // namespace hwmonio