examples: add unit testing example

examples/system/unit_test/components/testable/CMakeLists.txt

@@ -0,0 +1,4 @@
+set(COMPONENT_SRCS "mean.c")
+set(COMPONENT_ADD_INCLUDEDIRS "include")
+
+register_component()

examples/system/unit_test/components/testable/include/testable.h

@@ -0,0 +1,18 @@
+/* testable.h: Implementation of a testable component.
+
+   This example code is in the Public Domain (or CC0 licensed, at your option.)
+
+   Unless required by applicable law or agreed to in writing, this
+   software is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
+   CONDITIONS OF ANY KIND, either express or implied.
+*/
+
+#pragma once
+
+/**
+ * @brief Calculate arithmetic mean of integer values
+ * @param values  array of values
+ * @param count   number of elements in the array
+ * @return arithmetic mean of values, or zero count is zero
+ */
+int testable_mean(const int* values, int count);

examples/system/unit_test/components/testable/mean.c

@@ -0,0 +1,24 @@
+/* mean.c: Implementation of a mean function of testable component.
+   See test/test_mean.c for the associated unit test.
+
+   This example code is in the Public Domain (or CC0 licensed, at your option.)
+
+   Unless required by applicable law or agreed to in writing, this
+   software is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
+   CONDITIONS OF ANY KIND, either express or implied.
+*/
+
+#include "testable.h"
+
+
+int testable_mean(const int* values, int count)
+{
+    if (count == 0) {
+        return 0;
+    }
+    int sum = 0;
+    for (int i = 0; i < count; ++i) {
+        sum += values[i];
+    }
+    return sum / count;
+}

examples/system/unit_test/components/testable/test/CMakeLists.txt

@@ -0,0 +1,6 @@
+set(COMPONENT_SRCDIRS ".")
+set(COMPONENT_ADD_INCLUDEDIRS ".")
+
+set(COMPONENT_REQUIRES unity testable)
+
+register_component()

examples/system/unit_test/components/testable/test/component.mk

@@ -0,0 +1,7 @@
+# This is the minimal test component makefile.
+#
+# The following line is needed to force the linker to include all the object
+# files into the application, even if the functions in these object files
+# are not referenced from outside (which is usually the case for unit tests).
+# 
+COMPONENT_ADD_LDFLAGS = -Wl,--whole-archive -l$(COMPONENT_NAME) -Wl,--no-whole-archive

examples/system/unit_test/components/testable/test/test_mean.c

@@ -0,0 +1,36 @@
+/* test_mean.c: Implementation of a testable component.
+
+   This example code is in the Public Domain (or CC0 licensed, at your option.)
+
+   Unless required by applicable law or agreed to in writing, this
+   software is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
+   CONDITIONS OF ANY KIND, either express or implied.
+*/
+
+#include <limits.h>
+#include "unity.h"
+#include "testable.h"
+
+#define countof(x) (sizeof(x)/sizeof(x[0]))
+
+TEST_CASE("Mean of an empty array is zero", "[mean]")
+{
+    const int values[] = { 0 };
+    TEST_ASSERT_EQUAL(0, testable_mean(values, 0));
+}
+
+TEST_CASE("Mean of a test vector", "[mean]")
+{
+    const int v[] = {1, 3, 5, 7, 9};
+    TEST_ASSERT_EQUAL(5, testable_mean(v, countof(v)));
+}
+
+/* This test case currently fails, and developer has added a tag to indicate this.
+ * For the test runner, "[fails]" string does not carry any special meaning.
+ * However it can be used to filter out tests when running.
+ */
+TEST_CASE("Another test case which fails", "[mean][fails]")
+{
+    const int v1[] = {INT_MAX, INT_MAX, INT_MAX, INT_MAX};
+    TEST_ASSERT_EQUAL(INT_MAX, testable_mean(v1, countof(v1)));
+}