Improve error communication

codecov.yml

@@ -0,0 +1,2 @@
+codecov:
+  token: 9b033b7b-e22e-45e6-8aba-eccef3026c0e

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

@@ -6,8 +6,12 @@ def self.run(params)
           UI.user_error!("You have to install lizard using `[sudo] pip install lizard` or specify the executable path with the `:executable` option.")
         end
 
-        if params[:executable] && !File.exist?(params[:executable])
-          UI.user_error!("The custom executable at '#{params[:executable]}' does not exist.")
+        if params[:executable]
+          if !File.exist?(params[:executable])
+            UI.user_error!("The custom executable at '#{params[:executable]}' does not exist.")
+          elsif !File.file?(params[:executable])
+            UI.user_error!("You need to point to the executable to lizard.py file!")
+          end
         end
 
         lizard_command = params[:executable].nil? ? "lizard" : "python #{params[:executable]}"

spec/lizard_spec.rb

@@ -11,6 +11,7 @@
     let(:custom_executable) { "../spec/fixtures/lizard.py" }
     let(:outdated_executable) { "../spec/fixtures/outdated_lizard.py" }
     let(:newer_executable) { "../spec/fixtures/newer_lizard.py" }
+    let(:wrong_executable) { "../spec/fixtures" }
 
     context "executable" do
       it "fails with invalid sourcemap path" do
@@ -44,6 +45,17 @@
         end").runner.execute(:test)
       end
 
+      it "should raise if executable is wrong" do
+        expect(FastlaneCore::UI).to receive(:user_error!).with(/You need to point to the executable to lizard.py file\!/).and_call_original
+        expect do
+          Fastlane::FastFile.new.parse("lane :test do
+            lizard(
+              executable: '#{wrong_executable}'
+            )
+          end").runner.execute(:test)
+        end.to raise_error(/You need to point to the executable to lizard.py file\!/)
+      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         expect(FastlaneCore::UI).to receive(:user_error!).with(/Your lizard version .* is outdated, please upgrade to at least version .* and start your lane again\!/).and_call_original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