Improve behavior during dry-run when using Cypress globals

This fixes #1120 [1].

[1] #1120

CHANGELOG.md

@@ -2,6 +2,10 @@
 
 All notable changes to this project will be documented in this file.
 
+## Unreleased
+
+- Mock and imitate Cypress globals during diagnostics / dry run, fixes [#1120](https://github.com/badeball/cypress-cucumber-preprocessor/issues/1120).
+
 ## v19.1.0
 
 - Add `BeforeAll(..)` and `AfterAll(..)` hooks, fixes [#758](https://github.com/badeball/cypress-cucumber-preprocessor/issues/758).

docs/diagnostics.md

@@ -16,3 +16,23 @@ This supports some of the same flags as Cypress, including
 The intention here being that whatever flags you use to run `cypress run` can also be consumed by the executable to give appropriate diagnostics.
 
 > :warning:	This feature is especially experimental, it's subject to change anytime and is not considered under semver.
+
+## Limitations
+
+In order to obtain structured information about step definitions, these files are resolved and evaluated in a Node environment. This environment differs from the normal Cypress environment in that it's not a browser environment and Cypress globals are mocked and imitated to some degree.
+
+This means that expressions such as that shown below will work.
+
+```ts
+import { Given } from "@badeball/cypress-cucumber-preprocessor";
+
+const foo = Cypress.env("foo");
+
+Given("a step", () => {
+  if (foo) {
+    // ...
+  }
+});
+```
+
+However, other may not. Cypress globals are mocked on a best-effort and need-to-have basis. If you're code doesn't run correctly during diagnostics, you may open up an issue on the tracker.

features/diagnostics.feature

@@ -215,3 +215,77 @@ Feature: diagnostics
         │   a step       │ cypress/e2e/a.feature:3                     │
         └────────────────┴─────────────────────────────────────────────┘
         """
+
+  Rule: it should works despite accessing a variety of globals on root-level
+
+    Scenario: Cypress.env
+      Given a file named "cypress/e2e/a.feature" with:
+        """
+        Feature: a feature name
+          Scenario: a scenario name
+            Given a step
+        """
+      And a file named "cypress/support/step_definitions/steps.js" with:
+        """
+        const { Given } = require("@badeball/cypress-cucumber-preprocessor");
+        const foo = Cypress.env("foo");
+        Given("a step", function() {});
+        """
+      When I run diagnostics
+      Then the output should contain
+        """
+        ┌────────────────┬─────────────────────────────────────────────┐
+        │ Pattern / Text │ Location                                    │
+        ├────────────────┼─────────────────────────────────────────────┤
+        │ 'a step'       │ cypress/support/step_definitions/steps.js:3 │
+        │   a step       │ cypress/e2e/a.feature:3                     │
+        └────────────────┴─────────────────────────────────────────────┘
+        """
+
+    Scenario: Cypress.on
+      Given a file named "cypress/e2e/a.feature" with:
+        """
+        Feature: a feature name
+          Scenario: a scenario name
+            Given a step
+        """
+      And a file named "cypress/support/step_definitions/steps.js" with:
+        """
+        const { Given } = require("@badeball/cypress-cucumber-preprocessor");
+        Cypress.on("uncaught:exception", () => {});
+        Given("a step", function() {});
+        """
+      When I run diagnostics
+      Then the output should contain
+        """
+        ┌────────────────┬─────────────────────────────────────────────┐
+        │ Pattern / Text │ Location                                    │
+        ├────────────────┼─────────────────────────────────────────────┤
+        │ 'a step'       │ cypress/support/step_definitions/steps.js:3 │
+        │   a step       │ cypress/e2e/a.feature:3                     │
+        └────────────────┴─────────────────────────────────────────────┘
+        """
+
+    Scenario: Cypress.config
+      Given a file named "cypress/e2e/a.feature" with:
+        """
+        Feature: a feature name
+          Scenario: a scenario name
+            Given a step
+        """
+      And a file named "cypress/support/step_definitions/steps.js" with:
+        """
+        const { Given } = require("@badeball/cypress-cucumber-preprocessor");
+        const foo = Cypress.config("foo");
+        Given("a step", function() {});
+        """
+      When I run diagnostics
+      Then the output should contain
+        """
+        ┌────────────────┬─────────────────────────────────────────────┐
+        │ Pattern / Text │ Location                                    │
+        ├────────────────┼─────────────────────────────────────────────┤
+        │ 'a step'       │ cypress/support/step_definitions/steps.js:3 │
+        │   a step       │ cypress/e2e/a.feature:3                     │
+        └────────────────┴─────────────────────────────────────────────┘
+        """

lib/diagnostics/diagnose.ts

@@ -161,9 +161,17 @@ export async function diagnose(configuration: {
         );
       }
 
-      registry = withRegistry(true, () => {
-        (globalThis as any).Cypress = {};
+      const cypressMockGlobals = {
+        Cypress: {
+          env() {},
+          on() {},
+          config() {},
+        },
+      };
+
+      Object.assign(globalThis, cypressMockGlobals);
 
+      registry = withRegistry(true, () => {
         try {
           require(outputFileName);
         } catch (e: unknown) {