feat: throw error when using snapshot assertion with not (#5294)

packages/vitest/src/integrations/snapshot/chai.ts

@@ -52,6 +52,9 @@ export const SnapshotPlugin: ChaiPlugin = (chai, utils) => {
       chai.Assertion.prototype,
       key,
       function (this: Record<string, unknown>, properties?: object, message?: string) {
+        const isNot = utils.flag(this, 'negate')
+        if (isNot)
+          throw new Error(`${key} cannot be used with "not"`)
         const expected = utils.flag(this, 'object')
         const test = utils.flag(this, 'vitest-test')
         if (typeof properties === 'string' && typeof message === 'undefined') {
@@ -75,6 +78,9 @@ export const SnapshotPlugin: ChaiPlugin = (chai, utils) => {
     chai.Assertion.prototype,
     'toMatchFileSnapshot',
     function (this: Record<string, unknown>, file: string, message?: string) {
+      const isNot = utils.flag(this, 'negate')
+      if (isNot)
+        throw new Error('toMatchFileSnapshot cannot be used with "not"')
       const expected = utils.flag(this, 'object')
       const test = utils.flag(this, 'vitest-test') as Test
       const errorMessage = utils.flag(this, 'message')
@@ -98,6 +104,9 @@ export const SnapshotPlugin: ChaiPlugin = (chai, utils) => {
     chai.Assertion.prototype,
     'toMatchInlineSnapshot',
     function __INLINE_SNAPSHOT__(this: Record<string, unknown>, properties?: object, inlineSnapshot?: string, message?: string) {
+      const isNot = utils.flag(this, 'negate')
+      if (isNot)
+        throw new Error('toMatchInlineSnapshot cannot be used with "not"')
       const test = utils.flag(this, 'vitest-test')
       const isInsideEach = test && (test.each || test.suite?.each)
       if (isInsideEach)
@@ -129,6 +138,9 @@ export const SnapshotPlugin: ChaiPlugin = (chai, utils) => {
     chai.Assertion.prototype,
     'toThrowErrorMatchingSnapshot',
     function (this: Record<string, unknown>, message?: string) {
+      const isNot = utils.flag(this, 'negate')
+      if (isNot)
+        throw new Error('toThrowErrorMatchingSnapshot cannot be used with "not"')
       const expected = utils.flag(this, 'object')
       const test = utils.flag(this, 'vitest-test')
       const promise = utils.flag(this, 'promise') as string | undefined
@@ -145,6 +157,9 @@ export const SnapshotPlugin: ChaiPlugin = (chai, utils) => {
     chai.Assertion.prototype,
     'toThrowErrorMatchingInlineSnapshot',
     function __INLINE_SNAPSHOT__(this: Record<string, unknown>, inlineSnapshot: string, message: string) {
+      const isNot = utils.flag(this, 'negate')
+      if (isNot)
+        throw new Error('toThrowErrorMatchingInlineSnapshot cannot be used with "not"')
       const test = utils.flag(this, 'vitest-test')
       const isInsideEach = test && (test.each || test.suite?.each)
       if (isInsideEach)

test/fails/fixtures/snapshot-with-not.test.ts

@@ -0,0 +1,11 @@
+import { expect, test } from "vitest"
+
+test.each([
+  'toMatchSnapshot',
+  'toMatchFileSnapshot',
+  'toMatchInlineSnapshot',
+  'toThrowErrorMatchingSnapshot',
+  'toThrowErrorMatchingInlineSnapshot',
+])('%s should fail with not', (api) => {
+  (expect(0).not as any)[api]()
+})

test/fails/test/__snapshots__/runner.test.ts.snap

@@ -33,6 +33,14 @@ exports[`should fail nested-suite.test.ts > nested-suite.test.ts 1`] = `"Asserti
 
 exports[`should fail primitive-error.test.ts > primitive-error.test.ts 1`] = `"Unknown Error: 42"`;
 
+exports[`should fail snapshot-with-not.test.ts > snapshot-with-not.test.ts 1`] = `
+"Error: toThrowErrorMatchingInlineSnapshot cannot be used with "not"
+Error: toThrowErrorMatchingSnapshot cannot be used with "not"
+Error: toMatchInlineSnapshot cannot be used with "not"
+Error: toMatchFileSnapshot cannot be used with "not"
+Error: toMatchSnapshot cannot be used with "not""
+`;
+
 exports[`should fail stall.test.ts > stall.test.ts 1`] = `
 "TypeError: failure
 TypeError: failure