Add support for ARDUINO_CI_UNIT_TEST_EXTRA_COMPILER_FLAGS environment variable

Author: hlovdal

CHANGELOG.md

@@ -8,6 +8,8 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 ## [Unreleased]
 ### Added
 
+- Added support for `ARDUINO_CI_UNIT_TEST_EXTRA_COMPILER_FLAGS` environment variable.
+
 ### Changed
 
 ### Deprecated

REFERENCE.md

@@ -68,6 +68,23 @@ If set, testing will fail if no unit test files are detected (or if the director
 
 If set, testing will fail if no example sketches are detected.  This is to avoid communicating a passing status in cases where a commit may have accidentally moved or deleted the examples.
 
+### `ARDUINO_CI_UNIT_TEST_EXTRA_COMPILER_FLAGS` environment variable
+
+If you want to pass on additional flags to the compiler when it runs unit tests
+you can set this variable, e.g.
+
+```bash
+export ARDUINO_CI_UNIT_TEST_EXTRA_COMPILER_FLAGS="--coverage -g -O0"
+```
+
+By default the variable will be split up by space characters. If one of the
+flags contain spaces use the `ARDUINO_CI_TEST_EXTRA_COMPILER_FLAGS_DELIMITER`
+variable to chose a different delimiter, e.g.
+
+```bash
+export ARDUINO_CI_TEST_EXTRA_COMPILER_FLAGS_DELIMITER="|"
+export ARDUINO_CI_UNIT_TEST_EXTRA_COMPILER_FLAGS="-Wall|-DGREETING='Hello world'"
+```
 
 ## Indirectly Overriding Build Behavior (medium term use), and Advanced Options
 

lib/arduino_ci/cpp_library.rb

@@ -485,6 +485,18 @@ def test_args(aux_libraries, ci_gcc_config)
       ret
     end
 
+    # Allow users to inject extra compiler flags though environment variable.
+    def extra_compiler_flags_for_unittest
+      return [] unless ENV["ARDUINO_CI_UNIT_TEST_EXTRA_COMPILER_FLAGS"]
+
+      delimiter = if ENV["ARDUINO_CI_TEST_EXTRA_COMPILER_FLAGS_DELIMITER"]
+        yield(ENV["ARDUINO_CI_TEST_EXTRA_COMPILER_FLAGS_DELIMITER"])
+      else
+        " "
+      end
+      ENV["ARDUINO_CI_UNIT_TEST_EXTRA_COMPILER_FLAGS"].split(delimiter)
+    end
+
     # build a file for running a test of the given unit test file
     #
     # The dependent libraries configuration is appended with data from library.properties internal to the library under test
@@ -505,6 +517,7 @@ def build_for_test(test_file, gcc_binary)
         ]
       end
       arg_sets << @test_args
+      arg_sets << extra_compiler_flags_for_unittest
       arg_sets << [test_file.to_s, "-l#{LIBRARY_NAME}"]
       args = arg_sets.flatten(1)
       return nil unless run_gcc(gcc_binary, *args)
@@ -555,6 +568,7 @@ def build_shared_library(aux_libraries, gcc_binary, ci_gcc_config)
       @test_args = test_args(@full_dependencies, ci_gcc_config) # build full set of include directories to be cached for later
 
       arg_sets << @test_args
+      arg_sets << extra_compiler_flags_for_unittest
       arg_sets << cpp_files_arduino.map(&:to_s)  # Arduino.cpp, Godmode.cpp, and stdlib.cpp
       arg_sets << cpp_files_unittest.map(&:to_s) # ArduinoUnitTests.cpp
       arg_sets << cpp_files.map(&:to_s) # CPP files for the primary application library under test