使用PlatformIO+GoogleTest运行测试时.cpp文件链接失败问题

通过在platformio.ini中添加以下配置项，问题已解决：

build_src_filter =
    +<**/*.cpp>
    -<main.cpp>
test_build_src = yes

这是一个新手问题。我有一个简单的PlatformIO Arduino项目，目录结构如下：

project_root/
├── platformio.ini
├── src/
│   ├── Foo.cpp
│   ├── Foo.h
│   └── main.cpp
├── test/
│   └── test_desktop/
│       ├── bootstrap.cpp
│       └── foo_test.cpp

项目配置文件（platformio.ini） #

[env:nanoatmega328new]
platform = atmelavr
board = nanoatmega328new
framework = arduino
test_ignore = test_desktop

[env:native]
platform = native
test_ignore = test_embedded
lib_compat_mode = off
lib_deps = google/googletest@^1.15.2
build_flags = -std=c++14

源文件代码 #

src/main.cpp

#include <Arduino.h>
#include "Foo.h"

Foo foo;

void setup() {
  Serial.begin(9600);
}

void loop() {
  Serial.println(foo.bar());
}

src/Foo.h

#ifndef FOO_H
#define FOO_H

class Foo {
  public:
    int bar();
};

#endif //FOO_H

src/Foo.cpp

#include "Foo.h"

int Foo::bar() {
  return 0;
}

测试代码 #

test/test_desktop/bootstrap.cpp

#include <gtest/gtest.h>

int main(int argc, char **argv) {
  testing::InitGoogleTest(&argc, argv);
  return RUN_ALL_TESTS();
}

test/test_desktop/foo_test.cpp

#include <gtest/gtest.h>
#include "Foo.h"

TEST(Foo, test_bar) {
  Foo foo;
  ASSERT_EQ(foo.bar(), 0);
}

运行测试时的错误 #

执行pio test命令后出现以下错误：

Processing test_desktop in native environment
--------------------------------------------------------------------------------------------------------------------------------------------------------------------
Building...
Undefined symbols for architecture arm64:
  "Foo::bar()", referenced from:
      Foo_test_bar_Test::TestBody() in foo_test.o
ld: symbol(s) not found for architecture arm64
clang++: error: linker command failed with exit code 1 (use -v to see invocation)
*** [.pio/build/native/program] Error 1
Building stage has failed, see errors above. Use `pio test -vvv` option to enable verbose output.

问题表现为链接器无法找到Foo::bar()的实现，无法完成链接。

内容的提问来源于stack exchange，提问作者volodymyrkoval