test: backfill coverage for MiniPortile#activate

also:

- extract public methods `native_path` and `posix_path`
- fix LDFLAGS path on windows to use native path separators

lib/mini_portile2/mini_portile.rb

@@ -76,6 +76,24 @@ def self.target_cpu
     RbConfig::CONFIG['target_cpu']
   end
 
+  def self.native_path(path)
+    path = File.expand_path(path)
+    if File::ALT_SEPARATOR
+      path.tr(File::SEPARATOR, File::ALT_SEPARATOR)
+    else
+      path
+    end
+  end
+
+  def self.posix_path(path)
+    path = File.expand_path(path)
+    if File::ALT_SEPARATOR
+      "/" + path.tr(File::ALT_SEPARATOR, File::SEPARATOR).tr(":", File::SEPARATOR)
+    else
+      path
+    end
+  end
+
   def initialize(name, version, **kwargs)
     @name = name
     @version = version
@@ -240,7 +258,7 @@ def activate
 
     # rely on LDFLAGS when cross-compiling
     if File.exist?(lib_path) && (@host != @original_host)
-      full_path = File.expand_path(lib_path)
+      full_path = native_path(lib_path)
 
       old_value = ENV.fetch("LDFLAGS", "")
 
@@ -265,21 +283,11 @@ def make_cmd
   private
 
   def native_path(path)
-    path = File.expand_path(path)
-    if File::ALT_SEPARATOR
-      path.tr(File::SEPARATOR, File::ALT_SEPARATOR)
-    else
-      path
-    end
+    MiniPortile.native_path(path)
   end
 
   def posix_path(path)
-    path = File.expand_path(path)
-    if File::ALT_SEPARATOR
-      "/" + path.tr(File::ALT_SEPARATOR, File::SEPARATOR).tr(":", File::SEPARATOR)
-    else
-      path
-    end
+    MiniPortile.posix_path(path)
   end
 
   def tmp_path

test/test_activate.rb

@@ -0,0 +1,139 @@
+require File.expand_path('../helper', __FILE__)
+
+class TestActivate < TestCase
+  attr_reader :recipe
+
+  def setup
+    super
+
+    @save_env = %w[PATH CPATH LIBRARY_PATH LDFLAGS].inject({}) do |env, var|
+      env.update(var => ENV[var])
+    end
+
+    FileUtils.rm_rf(["tmp", "ports"]) # remove any previous test files
+
+    @recipe = MiniPortile.new("foo", "1.0.0").tap do |recipe|
+      recipe.logger = StringIO.new
+    end
+  end
+
+  def teardown
+    FileUtils.rm_rf(["tmp", "ports"]) # remove any previous test files
+
+    @save_env.each do |var, val|
+      ENV[var] = val
+    end
+
+    super
+  end
+
+  def test_PATH_env_var_when_bin_does_not_exist
+    ENV["PATH"] = "foo"
+    refute(Dir.exist?(bin_path))
+    refute_includes(path_elements('PATH'), bin_path)
+
+    recipe.activate
+
+    refute_includes(path_elements('PATH'), bin_path)
+  end
+
+  def test_PATH_env_var_when_bin_exists
+    ENV["PATH"] = "foo"
+    FileUtils.mkdir_p(bin_path)
+    refute_includes(path_elements('PATH'), bin_path)
+
+    recipe.activate
+
+    assert_includes(path_elements('PATH'), bin_path)
+    assert_equal(path_elements('PATH').first, bin_path)
+  end
+
+  def test_CPATH_env_var_when_include_does_not_exist
+    ENV["CPATH"] = "foo"
+    refute(Dir.exist?(include_path))
+    refute_includes(path_elements('CPATH'), include_path)
+
+    recipe.activate
+
+    refute_includes(path_elements('CPATH'), include_path)
+  end
+
+  def test_CPATH_env_var_when_include_exists
+    ENV["CPATH"] = "foo"
+    FileUtils.mkdir_p(include_path)
+    refute_includes(path_elements('CPATH'), include_path)
+
+    recipe.activate
+
+    assert_includes(path_elements('CPATH'), include_path)
+    assert_equal(path_elements('CPATH').first, include_path)
+  end
+
+  def test_LIBRARY_PATH_env_var_when_lib_does_not_exist
+    ENV["LIBRARY_PATH"] = "foo"
+    refute(Dir.exist?(lib_path))
+    refute_includes(path_elements('LIBRARY_PATH'), lib_path)
+
+    recipe.activate
+
+    refute_includes(path_elements('LIBRARY_PATH'), lib_path)
+  end
+
+  def test_LIBRARY_PATH_env_var_when_lib_exists
+    ENV["LIBRARY_PATH"] = "foo"
+    FileUtils.mkdir_p(lib_path)
+    refute_includes(path_elements('LIBRARY_PATH'), lib_path)
+
+    recipe.activate
+
+    assert_includes(path_elements('LIBRARY_PATH'), lib_path)
+    assert_equal(path_elements('LIBRARY_PATH').first, lib_path)
+  end
+
+  def test_LDFLAGS_env_var_when_not_cross_compiling
+    ENV["LDFLAGS"] = "-lfoo"
+    FileUtils.mkdir_p(lib_path)
+    assert_equal(recipe.host, recipe.original_host) # assert on setup)
+
+    refute_includes(flag_elements('LDFLAGS'), "-L#{lib_path}")
+
+    recipe.activate
+
+    refute_includes(flag_elements('LDFLAGS'), "-L#{lib_path}")
+  end
+
+  def test_LDFLAGS_env_var_when_cross_compiling
+    ENV["LDFLAGS"] = "-lfoo"
+    recipe.host = recipe.original_host + "-x" # make them not-equal
+    FileUtils.mkdir_p(lib_path)
+
+    refute_includes(flag_elements('LDFLAGS'), "-L#{lib_path}")
+
+    recipe.activate
+
+    assert_includes(flag_elements('LDFLAGS'), "-L#{lib_path}")
+    assert_equal(flag_elements('LDFLAGS').first, "-L#{lib_path}")
+  end
+
+  private
+
+  def path_elements(varname)
+    ENV.fetch(varname, "").split(File::PATH_SEPARATOR)
+  end
+
+  def flag_elements(varname)
+    ENV.fetch(varname, "").split
+  end
+
+  def bin_path
+    MiniPortile.native_path(File.join(recipe.path, "bin"))
+  end
+
+  def include_path
+    MiniPortile.native_path(File.join(recipe.path, "include"))
+  end
+
+  def lib_path
+    MiniPortile.native_path(File.join(recipe.path, "lib"))
+  end
+end