Use correct lizard command when custom executable is provided

lib/fastlane/plugin/lizard/actions/lizard_action.rb

@@ -10,16 +10,18 @@ def self.run(params)
           UI.user_error!("The custom executable at '#{params[:executable]}' does not exist.")
         end
 
-        lizard_cli_version = Gem::Version.new(`lizard --version`.scan(/(?:\d+\.?){3}/).first)
+        lizard_command = params[:executable].nil? ? "lizard" : "python #{params[:executable]}"
+
+        lizard_cli_version = Gem::Version.new(`#{lizard_command} --version 2>&1`.strip.scan(/(?:\d+\.?){3}/).first)
         required_version = Gem::Version.new(Fastlane::Lizard::CLI_VERSION)
         if lizard_cli_version < required_version
-          UI.user_error!("Your lizard version is outdated, please upgrade to at least version #{Fastlane::Lizard::CLI_VERSION} and start your lane again!")
+          UI.user_error!("Your lizard version #{lizard_cli_version} is outdated, please upgrade to at least version #{required_version} and start your lane again!")
         end
 
-        command = forming_command(params)
+        command = forming_command(lizard_command, params)
 
         if params[:show_warnings]
-          Fastlane::Actions.sh_control_output("lizard #{params[:source_folder]} | sed -n -e '/^$/,$p'", print_command: true, print_command_output: true)
+          Fastlane::Actions.sh_control_output("#{lizard_command} #{params[:source_folder]} | sed -n -e '/^$/,$p'", print_command: true, print_command_output: true)
         end
 
         begin
@@ -30,10 +32,9 @@ def self.run(params)
         end
       end
 
-      def self.forming_command(params)
+      def self.forming_command(lizard_command, params)
         command = []
-        command << 'lizard' unless params[:executable]
-        command << "python #{params[:executable]}" if params[:executable]
+        command << lizard_command
         command << params[:language].split(",").map { |l| "-l #{l.strip}" }.join(" ") if params[:language]
         command << "--#{params[:export_type]}" if params[:export_type]
         command << "-C #{params[:ccn]}" if params[:ccn] # stands for cyclomatic complexity number

spec/fixtures/lizard.py

@@ -0,0 +1,2 @@
+# Imitate "lizard.py --version" command by default.
+print("1.14.10") # Matches contents of version.rb.

spec/fixtures/newer_lizard.py

@@ -0,0 +1,2 @@
+# Imitate "lizard.py --version" command by default.
+print("2.0.0")

spec/fixtures/outdated_lizard.py

@@ -0,0 +1,2 @@
+# Imitate "lizard.py --version" command by default.
+print("1.0.0")

spec/lizard_spec.rb

@@ -8,6 +8,9 @@
     let(:ccn) { 10 }
     let(:length) { 800 }
     let(:working_threads) { 3 }
+    let(:custom_executable) { "../spec/fixtures/lizard.py" }
+    let(:outdated_executable) { "../spec/fixtures/outdated_lizard.py" }
+    let(:newer_executable) { "../spec/fixtures/newer_lizard.py" }
 
     context "executable" do
       it "fails with invalid sourcemap path" do
@@ -22,6 +25,37 @@
       end
     end
 
+    context "required version" do
+      it "should not raise if executable version is same as required" do
+        expect(FastlaneCore::UI).to_not(receive(:user_error!))
+        Fastlane::FastFile.new.parse("lane :test do
+          lizard(
+            executable: '#{custom_executable}'
+          )
+        end").runner.execute(:test)
+      end
+
+      it "should not raise if executable version is newer than required" do
+        expect(FastlaneCore::UI).to_not(receive(:user_error!))
+        Fastlane::FastFile.new.parse("lane :test do
+          lizard(
+            executable: '#{newer_executable}'
+          )
+        end").runner.execute(:test)
+      end
+
+      it "should raise if executable version is less than required" do
+        expect(FastlaneCore::UI).to receive(:user_error!).with(/Your lizard version .* is outdated, please upgrade to at least version .* and start your lane again\!/).and_call_original
+        expect do
+          Fastlane::FastFile.new.parse("lane :test do
+            lizard(
+              executable: '#{outdated_executable}'
+            )
+          end").runner.execute(:test)
+        end.to raise_error(/Your lizard version .* is outdated, please upgrade to at least version .* and start your lane again\!/)
+      end
+    end
+
     context "default use case" do
       it "default language as swift" do
         result = Fastlane::FastFile.new.parse("lane :test do
@@ -36,11 +70,11 @@
       it "uses custom executable" do
         result = Fastlane::FastFile.new.parse("lane :test do
           lizard(
-            executable: '../spec/fixtures/lizard.py'
+            executable: '#{custom_executable}'
           )
         end").runner.execute(:test)
 
-        expect(result).to eq("python ../spec/fixtures/lizard.py -l swift")
+        expect(result).to eq("python #{custom_executable} -l swift")
       end
 
       it "should raise if custom executable does not exist" do