test: Add test to demonstrate usage of code coverage

test/coverage/.bazelrc

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+common --registry=https://raw.githubusercontent.com/eclipse-score/bazel_registry/main/
+common --registry=https://bcr.bazel.build

test/coverage/BUILD

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+cc_library(
+    name = "coverage_lib",
+    srcs = ["coverage.cpp"],
+    hdrs = ["coverage.h"],
+    deps = ["//greeting:greeting"],
+)
+
+cc_binary(
+    name = "coverage",
+    srcs = ["main.cpp"],
+    deps = [
+        ":coverage_lib",
+    ],
+)
+
+cc_test(
+    name = "coverage_test",
+    srcs = ["coverage_test.cpp"],
+    deps = [
+        ":coverage_lib",
+        "//greeting:greeting",
+        "@googletest//:gtest",
+        "@googletest//:gtest_main",
+    ],
+    size="small",
+)
+
+# Test suite for all components (individual tests)
+test_suite(
+    name = "all_tests",
+    tests = [
+        ":coverage_test",
+    ],
+)

test/coverage/MODULE.bazel

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+module(
+    name = "coverage_test",
+    version = "0.1.0",
+    compatibility_level = 0,
+)
+
+# bazel cc rules
+bazel_dep(name = "rules_cc", version = "0.1.1")
+
+#score gcc toolchain
+bazel_dep(name = "score_toolchains_gcc", version = "0.5", dev_dependency = False)
+
+gcc = use_extension("@score_toolchains_gcc//extentions:gcc.bzl", "gcc", dev_dependency = False)
+gcc.toolchain(
+    sha256 = "8fa85c2a93a6bef1cf866fa658495a2416dfeec692e4246063b791abf18da083",
+    strip_prefix = "x86_64-unknown-linux-gnu",
+    url = "https://github.com/eclipse-score/toolchains_gcc_packages/releases/download/v0.0.3/x86_64-unknown-linux-gnu_gcc12.tar.gz",
+)
+use_repo(gcc, "gcc_toolchain", "gcc_toolchain_gcc")
+
+register_toolchains("@gcc_toolchain//:all")
+
+bazel_dep(name = "googletest", version = "1.17.0.bcr.1", dev_dependency = True)

test/coverage/README.md

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+Sample to generate coverage data
+================================
+
+This directory contains a sample C++ project with test coverage capabilities using Bazel and GCC's gcov/lcov tools.
+
+## Prerequisites
+
+Ensure you have the following tools installed:
+- Bazel
+- lcov (Linux Test Project coverage tools)
+
+On Ubuntu/Debian:
+```bash
+sudo apt-get install lcov
+```
+
+## Running Tests with Coverage
+
+### Step 1: Run tests with coverage collection
+
+To generate coverage data for the `all_tests` target, run:
+
+```bash
+$ bazel coverage --combined_report=lcov --subcommands -- //:all_tests
+```
+
+### Step 2: View coverage summary with lcov
+
+To get a quick coverage summary using lcov, you need to find the generated coverage files and use lcov:
+
+```bash
+$ lcov --summary --rc branch_coverage=1 bazel-out/_coverage/_coverage_report.dat
+Summary coverage rate:
+  lines......: 100.0% (10 of 10 lines)
+  functions..: 100.0% (2 of 2 functions)
+  branches...: 100.0% (4 of 4 branches)
+```
+
+Alternatively, you can use the coverage files directly from the bazel-out directory:
+
+```bash
+# Find all .gcno and .gcda files
+find -L bazel-out/ -name "*.gcda" -o -name "*.gcno" | head -10
+
+# Generate coverage info file
+lcov --capture --directory bazel-out --output-file coverage.info
+
+# Show coverage summary
+lcov --summary coverage.info
+```

test/coverage/coverage.cpp

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+#include "coverage.h"
+#include "greeting/greeting.h"
+
+namespace coverage {
+
+// Extracted main logic for testing
+void runMain(int argc, char* argv[]) noexcept {
+    if (argc > 1) {
+        greeting::printGreeting(argv[1]);
+    } else {
+        greeting::printGreeting("World");
+    }
+}
+
+}  // namespace coverage

test/coverage/coverage.h

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+#ifndef COVERAGE_COVERAGE_H
+#define COVERAGE_COVERAGE_H
+
+namespace coverage {
+
+// Function to run main logic (extracted for testing)
+void runMain(int argc, char* argv[]) noexcept;
+
+}  // namespace coverage
+
+#endif  // COVERAGE_COVERAGE_H

test/coverage/coverage_test.cpp

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+#include "coverage.h"
+#include "greeting/greeting.h"
+#include <gtest/gtest.h>
+#include <sstream>
+#include <iostream>
+
+// Helper class to capture cout output
+class CoutCapture {
+public:
+    CoutCapture() {
+        old_cout_buffer = std::cout.rdbuf();
+        std::cout.rdbuf(captured_output.rdbuf());
+    }
+
+    ~CoutCapture() {
+        std::cout.rdbuf(old_cout_buffer);
+    }
+
+    std::string getOutput() {
+        return captured_output.str();
+    }
+
+private:
+    std::streambuf* old_cout_buffer;
+    std::ostringstream captured_output;
+};
+
+// =============================================================================
+// MAIN FUNCTION TESTS
+// =============================================================================
+
+// Test fixture class for main functionality
+class CoverageTest : public ::testing::Test {
+protected:
+    void SetUp() override {
+        // Setup code if needed
+    }
+
+    void TearDown() override {
+        // Cleanup code if needed
+    }
+};
+
+// Test main function with no arguments (argc = 1) - should greet "World"
+TEST_F(CoverageTest, MainWithNoArguments) {
+    CoutCapture capture;
+    const char* argv[] = {"./hello"};
+    coverage::runMain(1, const_cast<char**>(argv));
+    std::string output = capture.getOutput();
+
+    EXPECT_EQ(output, "Hello, World!\n");
+}
+
+// Test main function with one argument - should greet that argument
+TEST_F(CoverageTest, MainWithOneArgument) {
+    CoutCapture capture;
+    const char* argv[] = {"./hello", "Alice"};
+    coverage::runMain(2, const_cast<char**>(argv));
+    std::string output = capture.getOutput();
+
+    EXPECT_EQ(output, "Hello, Alice!\n");
+}
+
+// Test main function with "Uwe" argument - should trigger special greeting
+TEST_F(CoverageTest, MainWithUweArgument) {
+    CoutCapture capture;
+    const char* argv[] = {"./hello", "Uwe"};
+    coverage::runMain(2, const_cast<char**>(argv));
+    std::string output = capture.getOutput();
+
+    EXPECT_EQ(output, "Hello there, Uwe! Great to see you!\n");
+}
+
+// Test main function with multiple arguments - should only use the first one
+TEST_F(CoverageTest, MainWithMultipleArguments) {
+    CoutCapture capture;
+    const char* argv[] = {"./hello", "Bob", "Charlie", "David"};
+    coverage::runMain(4, const_cast<char**>(argv));
+    std::string output = capture.getOutput();
+
+    EXPECT_EQ(output, "Hello, Bob!\n");
+}
+
+// Test edge case: argc = 0 (unusual but possible)
+TEST_F(CoverageTest, MainWithZeroArgc) {
+    CoutCapture capture;
+    const char* argv[] = {};
+    coverage::runMain(0, const_cast<char**>(argv));
+    std::string output = capture.getOutput();
+
+    EXPECT_EQ(output, "Hello, World!\n");
+}
+
+// =============================================================================
+// GREETING LIBRARY TESTS
+// =============================================================================
+
+// Test fixture class for greeting library
+class GreetingTest : public ::testing::Test {
+protected:
+    void SetUp() override {
+        // Setup code if needed
+    }
+
+    void TearDown() override {
+        // Cleanup code if needed
+    }
+};
+
+// Test case for greeting "Uwe" - should trigger special greeting
+TEST_F(GreetingTest, GreetingForUwe) {
+    CoutCapture capture;
+    greeting::printGreeting("Uwe");
+    std::string output = capture.getOutput();
+
+    EXPECT_EQ(output, "Hello there, Uwe! Great to see you!\n");
+}
+
+// Test case for greeting any other name - should trigger regular greeting
+TEST_F(GreetingTest, GreetingForRegularName) {
+    CoutCapture capture;
+    greeting::printGreeting("Alice");
+    std::string output = capture.getOutput();
+
+    EXPECT_EQ(output, "Hello, Alice!\n");
+}
+
+// Test case for empty string
+TEST_F(GreetingTest, GreetingForEmptyString) {
+    CoutCapture capture;
+    greeting::printGreeting("");
+    std::string output = capture.getOutput();
+
+    EXPECT_EQ(output, "Hello, !\n");
+}
+
+// Test case for "World" - typical default case
+TEST_F(GreetingTest, GreetingForWorld) {
+    CoutCapture capture;
+    greeting::printGreeting("World");
+    std::string output = capture.getOutput();
+
+    EXPECT_EQ(output, "Hello, World!\n");
+}
+
+// Test case for case sensitivity - "uwe" (lowercase) should not trigger special greeting
+TEST_F(GreetingTest, GreetingForLowercaseUwe) {
+    CoutCapture capture;
+    greeting::printGreeting("uwe");
+    std::string output = capture.getOutput();
+
+    EXPECT_EQ(output, "Hello, uwe!\n");
+}
+
+// Test case for case sensitivity - "UWE" (uppercase) should not trigger special greeting
+TEST_F(GreetingTest, GreetingForUppercaseUWE) {
+    CoutCapture capture;
+    greeting::printGreeting("UWE");
+    std::string output = capture.getOutput();
+
+    EXPECT_EQ(output, "Hello, UWE!\n");
+}
+
+// Test case for string containing "Uwe" but not exactly "Uwe"
+TEST_F(GreetingTest, GreetingForStringContainingUwe) {
+    CoutCapture capture;
+    greeting::printGreeting("Uwe Müller");
+    std::string output = capture.getOutput();
+
+    EXPECT_EQ(output, "Hello, Uwe Müller!\n");
+}
+
+// Test case for numeric input
+TEST_F(GreetingTest, GreetingForNumericInput) {
+    CoutCapture capture;
+    greeting::printGreeting("123");
+    std::string output = capture.getOutput();
+
+    EXPECT_EQ(output, "Hello, 123!\n");
+}
+
+// Test case for special characters
+TEST_F(GreetingTest, GreetingForSpecialCharacters) {
+    CoutCapture capture;
+    greeting::printGreeting("@#$%");
+    std::string output = capture.getOutput();
+
+    EXPECT_EQ(output, "Hello, @#$%!\n");
+}

test/coverage/greeting/BUILD

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+cc_library(
+    name = "greeting",
+    srcs = ["greeting.cpp"],
+    hdrs = ["greeting.h"],
+    visibility = ["//:__subpackages__"],
+)

test/coverage/greeting/greeting.cpp

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+#include "greeting.h"
+#include <iostream>
+
+namespace greeting {
+
+void printGreeting(const std::string& name) noexcept {
+    if (name == "Uwe") {
+        std::cout << "Hello there, Uwe! Great to see you!" << std::endl;
+    } else {
+        std::cout << "Hello, " << name << "!" << std::endl;
+    }
+}
+
+}  // namespace greeting

test/coverage/greeting/greeting.h

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+#ifndef GREETING_GREETING_H
+#define GREETING_GREETING_H
+
+#include <string>
+
+namespace greeting {
+
+void printGreeting(const std::string& name) noexcept;
+
+}  // namespace greeting
+
+#endif  // GREETING_GREETING_H

test/coverage/main.cpp

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+#include "coverage.h"
+
+int main(int argc, char* argv[]) {
+    coverage::runMain(argc, argv);
+    return 0;
+}