Exam: Hysteresis¶
Requirement¶
Implement a class Hysteresis (a Thermostat) that works as follows.
It uses a sensor (
MockSensor) to measure the temperatureIt controls a switch (a
MockSwitch)If the temperature falls below a certain configurable low threshold, the switch is set to on (heating is turned on)
If the temperature rises above a certain configurable high threshold, the switch is set to off (heating is turned on)
Use the following tests to drive you through the exercise:
#include <gtest/gtest.h>
#include <sensor-mock.h>
#include <switch-mock.h>
#include <hysteresis.h>
TEST(hysteresis_suite, nop_when_within_range)
{
MockSensor sensor(30.2);
MockSwitch switcH(MockSwitch::OFF);
Hysteresis hyst(&sensor, &switcH, 20.1, 30.4);
hyst.check(); // <--- sees sensor well within range
ASSERT_EQ(switcH.state(), MockSwitch::OFF);
}
#include <gtest/gtest.h>
#include <sensor-mock.h>
#include <switch-mock.h>
#include <hysteresis.h>
TEST(hysteresis_suite, falls_below_range)
{
MockSensor sensor(30.2);
MockSwitch switcH(MockSwitch::OFF);
Hysteresis hyst(&sensor, &switcH,
20.1, 30.4); // <--- initially within range
hyst.check();
ASSERT_EQ(switcH.state(), MockSwitch::OFF);
sensor.set_temperature(20.0); // <--- falls below range
hyst.check();
ASSERT_EQ(switcH.state(), MockSwitch::ON);
}
#include <gtest/gtest.h>
#include <sensor-mock.h>
#include <switch-mock.h>
#include <hysteresis.h>
TEST(hysteresis_suite, rises_above_range)
{
MockSensor sensor(30.2);
MockSwitch switcH(MockSwitch::OFF);
Hysteresis hyst(&sensor, &switcH, 20.1, 30.4);
hyst.check();
ASSERT_EQ(switcH.state(), MockSwitch::OFF);
sensor.set_temperature(35); // <--- rises above range
hyst.check();
ASSERT_EQ(switcH.state(), MockSwitch::OFF);
}
#include <gtest/gtest.h>
#include <sensor-mock.h>
#include <switch-mock.h>
#include <hysteresis.h>
TEST(hysteresis_suite, rises_above_range_when_on)
{
MockSensor sensor(30.2);
MockSwitch switcH(MockSwitch::OFF);
Hysteresis hyst(&sensor, &switcH, 20.1, 30.4);
sensor.set_temperature(-273.15); // <--- ensure that switch will be
// on after next check()
hyst.check();
ASSERT_EQ(switcH.state(), MockSwitch::ON);
sensor.set_temperature(35); // <--- rises above range
hyst.check();
ASSERT_EQ(switcH.state(), MockSwitch::OFF);
}
Work Instructions¶
In the following, ~/My-Projects and ~/My-Builds are
placeholders for directory name that you may choose.
~/My-Projectscontains code written by you~/My-Buildscontains builds, i.e. material that can be removed and recreated
Preparation¶
Download dtle-2024.tar.bz2 jjj
Unpack into source directory
$ cd ~/My-Projects $ tar -x -j -f path/to/dtle-2024.tar.bz2
Create build directory, and change into it
$ mkdir ~/My-Builds/dtle-2024-build $ cd ~/My-Builds/dtle-2024-build
Build what you downloaded (CWD is ~/My-Builds/dtle-2024-build)
$ pwd $ ~/My-Builds/dtle-2024-build $ cmake ~/My-Projects/dtle-2024 ... roedel ... $ make ... roedel ...
Check project state: test failures
$ pwd $ ~/My-Builds/dtle-2024-build $ ./tests/dtle-hysteresis-suite Running main() from ~/My-Projects/dtle-2024/googletest/googletest/src/gtest_main.cc [==========] Running 4 tests from 1 test suite. [----------] Global test environment set-up. [----------] 4 tests from hysteresis_suite [ RUN ] hysteresis_suite.falls_below_range ~/My-Projects/dtle-2024/tests/hysteresis-falls_below_range.cpp:20: Failure Expected equality of these values: switcH.state() Which is: 1 MockSwitch::ON Which is: 0 [ FAILED ] hysteresis_suite.falls_below_range (0 ms) [ RUN ] hysteresis_suite.nop_when_within_range [ OK ] hysteresis_suite.nop_when_within_range (0 ms) [ RUN ] hysteresis_suite.rises_above_range [ OK ] hysteresis_suite.rises_above_range (0 ms) [ RUN ] hysteresis_suite.rises_above_range_when_on ~/My-Projects/dtle-2024/tests/hysteresis-rises_above_range_when_on.cpp:17: Failure Expected equality of these values: switcH.state() Which is: 1 MockSwitch::ON Which is: 0 [ FAILED ] hysteresis_suite.rises_above_range_when_on (0 ms) [----------] 4 tests from hysteresis_suite (0 ms total) [----------] Global test environment tear-down [==========] 4 tests from 1 test suite ran. (0 ms total) [ PASSED ] 2 tests. [ FAILED ] 2 tests, listed below: [ FAILED ] hysteresis_suite.falls_below_range [ FAILED ] hysteresis_suite.rises_above_range_when_on 2 FAILED TESTS
Implementation¶
In
~/My-Project/toolcase, you’ll find two files,hysteresis.hhysteresis.cpp
Fix the code in these files.
These are the only files that must be modified! Do not modify anything else!
Repeat the cycle
Modify code
Build (
make)Test (
./tests/dtle-hysteresis-suite)
until all tests are green
$ ./tests/dtle-hysteresis-suite Running main() from ~/My-Projects/dtle-2024/googletest/googletest/src/gtest_main.cc [==========] Running 4 tests from 1 test suite. [----------] Global test environment set-up. [----------] 4 tests from hysteresis_suite [ RUN ] hysteresis_suite.falls_below_range [ OK ] hysteresis_suite.falls_below_range (0 ms) [ RUN ] hysteresis_suite.nop_when_within_range [ OK ] hysteresis_suite.nop_when_within_range (0 ms) [ RUN ] hysteresis_suite.rises_above_range [ OK ] hysteresis_suite.rises_above_range (0 ms) [ RUN ] hysteresis_suite.rises_above_range_when_on [ OK ] hysteresis_suite.rises_above_range_when_on (0 ms) [----------] 4 tests from hysteresis_suite (0 ms total) [----------] Global test environment tear-down [==========] 4 tests from 1 test suite ran. (0 ms total) [ PASSED ] 4 tests.
Submission¶
Archive the project state into a compressed .tar archive,
$ cd ~/My-Projects/
$ tar -z -c -f dtle-2024.tar.gz dtle-2024/
Submit the archive dtle-2024.tar.gz to Moodle.