Filter non-feature specs as if containing an empty set of tags

This fixes #1116 [1].

[1] #1116

CHANGELOG.md

@@ -6,6 +6,10 @@ All notable changes to this project will be documented in this file.
 
 - Mock and imitate Cypress globals during diagnostics / dry run, fixes [#1120](https://github.com/badeball/cypress-cucumber-preprocessor/issues/1120).
 
+- Avoid filtering non-feature specs upon tag expressions containing negating expressions, fixes [#1116](https://github.com/badeball/cypress-cucumber-preprocessor/issues/1116).
+
+  - Non-feature specs are filtered as if containing an empty set of tags.
+
 ## v19.1.0
 
 - Add `BeforeAll(..)` and `AfterAll(..)` hooks, fixes [#758](https://github.com/badeball/cypress-cucumber-preprocessor/issues/758).

features/tags/spec_filter.feature

@@ -1,31 +1,73 @@
 Feature: filter spec
 
-  Scenario: 1 / 2 specs matching
+  Background:
     Given additional preprocessor configuration
       """
       {
         "filterSpecs": true
       }
       """
-    And a file named "cypress/e2e/a.feature" with:
-      """
-      @foo
-      Feature: some feature
-        Scenario: first scenario
-          Given a step
-      """
-    And a file named "cypress/e2e/b.feature" with:
-      """
-      @bar
-      Feature: some other feature
-        Scenario: second scenario
-          Given a step
-      """
-    And a file named "cypress/support/step_definitions/steps.js" with:
-      """
-      const { Given } = require("@badeball/cypress-cucumber-preprocessor");
-      Given("a step", function() {})
-      """
-    When I run cypress with "--env tags=@foo"
-    Then it passes
-    And it should appear to not have ran spec "b.feature"
+
+  Rule: it should filter features based on whether they contain a matching scenario
+
+    Scenario: 1 / 2 specs matching
+      Given a file named "cypress/e2e/a.feature" with:
+        """
+        @foo
+        Feature: some feature
+          Scenario: first scenario
+            Given a step
+        """
+      And a file named "cypress/e2e/b.feature" with:
+        """
+        @bar
+        Feature: some other feature
+          Scenario: second scenario
+            Given a step
+        """
+      And a file named "cypress/support/step_definitions/steps.js" with:
+        """
+        const { Given } = require("@badeball/cypress-cucumber-preprocessor");
+        Given("a step", function() {})
+        """
+      When I run cypress with "--env tags=@foo"
+      Then it passes
+      And it should appear to not have ran spec "b.feature"
+
+  Rule: non-feature specs should be filtered as if they have tags equalling the empty set
+
+    Background:
+      Given additional Cypress configuration
+        """
+        {
+          "e2e": {
+            "specPattern": "**/*.{spec.js,feature}"
+          }
+        }
+        """
+      And a file named "cypress/e2e/a.feature" with:
+        """
+        @bar
+        Feature: some feature
+          Scenario: first scenario
+            Given a step
+        """
+      And a file named "cypress/support/step_definitions/steps.js" with:
+        """
+        const { Given } = require("@badeball/cypress-cucumber-preprocessor");
+        Given("a step", function() {})
+        """
+      And a file named "cypress/e2e/b.spec.js" with:
+        """
+        it("should work", () => {});
+        """
+
+    Scenario: logical not
+      When I run cypress with "--env 'tags=not @foo'"
+      Then it passes
+      And it should appear to have ran spec "a.feature" and "b.spec.js"
+
+    Scenario: not logical not
+      When I run cypress with "--env tags=@bar"
+      Then it passes
+      And it should appear as if only a single test ran

lib/add-cucumber-preprocessor-plugin.ts

@@ -136,6 +136,10 @@ export async function addCucumberPreprocessorPlugin(
     const testFiles = getTestFiles(
       config as unknown as ICypressConfiguration
     ).filter((testFile) => {
+      if (!testFile.endsWith(".feature")) {
+        return node.evaluate([]);
+      }
+
       const content = fs.readFileSync(testFile).toString("utf-8");
 
       const options = {