Use the provided crate type when running tests

Fixes #982

Author: shepmaster

tests/spec/features/test_action_spec.rb

@@ -0,0 +1,32 @@
+require 'spec_helper'
+require 'support/editor'
+require 'support/playground_actions'
+
+RSpec.feature "Testing the code", type: :feature, js: true do
+  include PlaygroundActions
+
+  before { visit '/' }
+
+  scenario "when a crate type is provided" do
+    code = <<~EOF
+      #![crate_type = "proc-macro"]
+
+      use proc_macro::TokenStream;
+
+      #[proc_macro]
+      pub fn demo(input: TokenStream) -> TokenStream {
+          input
+      }
+    EOF
+    editor.set(code)
+
+    in_build_menu { click_on(build_button: "Test") }
+    within(:output, :stdout) do
+      expect(page).to have_content "running 0 tests"
+    end
+  end
+
+  def editor
+    Editor.new(page)
+  end
+end

ui/frontend/actions.ts

@@ -263,7 +263,11 @@ function performAutoOnly(): ThunkAction {
 
 const performExecuteOnly = (): ThunkAction => performCommonExecute('bin', false);
 const performCompileOnly = (): ThunkAction => performCommonExecute('lib', false);
-const performTestOnly = (): ThunkAction => performCommonExecute('lib', true);
+const performTestOnly = (): ThunkAction => (dispatch, getState) => {
+  const state = getState();
+  const crateType = getCrateType(state);
+  return dispatch(performCommonExecute(crateType, true));
+};
 
 interface GenericApiFailure {
   error: string;