Fixed lengthy stacktrace when running cucumber -f stepdefs when ste…

…ps aren't defined (#1286)

features/docs/formatters/usage_formatter.feature

@@ -99,3 +99,25 @@ Feature: Usage formatter
         11 steps (11 skipped)
 
         """
+
+    Scenario: Run with --format stepdefs when some steps are undefined
+      Given a file named "features/calculator.feature" with:
+      """
+      Feature: Calculator
+        Scenario: Adding numbers
+          When I add 4 and 5
+          Then I should get 9
+      """
+      When I run `cucumber -f stepdefs features/calculator.feature`
+      Then it should pass with:
+      """
+      You can implement step definitions for undefined steps with these snippets:
+
+      When("I add {int} and {int}") do |int, int2|
+        pending # Write code here that turns the phrase above into concrete actions
+      end
+
+      Then("I should get {int}") do |int|
+        pending # Write code here that turns the phrase above into concrete actions
+      end
+      """

lib/cucumber/formatter/usage.rb

@@ -38,19 +38,23 @@ def on_test_step_finished(event)
         test_step = event.test_step
         result = event.result.with_filtered_backtrace(Cucumber::Formatter::BacktraceFilter)
         step_match = @matches[test_step.source]
-        step_definition = step_match.step_definition
-        stepdef_key = StepDefKey.new(step_definition.expression.to_s, step_definition.location)
-        unless @stepdef_to_match[stepdef_key].map { |key| key[:location] }.include? test_step.location
-          duration = DurationExtractor.new(result).result_duration
-
-          @stepdef_to_match[stepdef_key] << {
-            keyword: test_step.source.last.keyword,
-            step_match: step_match,
-            status: result.to_sym,
-            location: test_step.location,
-            duration: duration
-          }
+
+        unless step_match.nil?
+          step_definition = step_match.step_definition
+          stepdef_key = StepDefKey.new(step_definition.expression.to_s, step_definition.location)
+          unless @stepdef_to_match[stepdef_key].map { |key| key[:location] }.include? test_step.location
+            duration = DurationExtractor.new(result).result_duration
+
+            @stepdef_to_match[stepdef_key] << {
+              keyword: test_step.source.last.keyword,
+              step_match: step_match,
+              status: result.to_sym,
+              location: test_step.location,
+              duration: duration
+            }
+          end
         end
+
         super
       end