Make test fail on environments that don't have Path set

test/fast/environment-test.ts

@@ -37,11 +37,27 @@ describe('environment variables', () => {
     }
   })
 
-  it('resulting PATH contains the original PATH', async () => {
-    // This test will ensure that on platforms where env vars names are
-    // case-insensitive (like Windows) we don't end up with an invalid PATH
-    // and the original one lost in the process.
-    const { env } = await setupEnvironment({})
-    expect((<any>env)['PATH']).toContain(process.env.PATH)
-  })
+  if (process.platform === 'win32') {
+    it('resulting PATH contains the original PATH', () => {
+      const originalPathKey = Object.keys(process.env).find(
+        k => k.toUpperCase() === 'PATH'
+      )
+      expect(originalPathKey).not.toBeUndefined()
+
+      const originalPathValue = process.env.PATH
+
+      try {
+        delete process.env.PATH
+        process.env.Path = 'wow-such-case-insensitivity'
+        // This test will ensure that on platforms where env vars names are
+        // case-insensitive (like Windows) we don't end up with an invalid PATH
+        // and the original one lost in the process.
+        const { env } = setupEnvironment({})
+        expect(env.PATH).toContain('wow-such-case-insensitivity')
+      } finally {
+        delete process.env.Path
+        process.env[originalPathKey!] = originalPathValue
+      }
+    })
+  }
 })