fix: show custom error message if snapshot failed

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

@@ -36,7 +36,15 @@ export const SnapshotPlugin: ChaiPlugin = (chai, utils) => {
           message = properties
           properties = undefined
         }
-        getSnapshotClient().assert(expected, test, message, false, properties)
+        const errorMessage = utils.flag(this, 'message')
+        getSnapshotClient().assert({
+          received: expected,
+          test,
+          message,
+          isInline: false,
+          properties,
+          errorMessage,
+        })
       },
     )
   }
@@ -54,7 +62,17 @@ export const SnapshotPlugin: ChaiPlugin = (chai, utils) => {
       }
       if (inlineSnapshot)
         inlineSnapshot = stripSnapshotIndentation(inlineSnapshot)
-      getSnapshotClient().assert(expected, test, message, true, properties, inlineSnapshot, error)
+      const errorMessage = utils.flag(this, 'message')
+      getSnapshotClient().assert({
+        received: expected,
+        test,
+        message,
+        isInline: true,
+        properties,
+        inlineSnapshot,
+        error,
+        errorMessage,
+      })
     },
   )
   utils.addMethod(
@@ -63,7 +81,13 @@ export const SnapshotPlugin: ChaiPlugin = (chai, utils) => {
     function (this: Record<string, unknown>, message?: string) {
       const expected = utils.flag(this, 'object')
       const test = utils.flag(this, 'vitest-test')
-      getSnapshotClient().assert(getErrorString(expected), test, message)
+      const errorMessage = utils.flag(this, 'message')
+      getSnapshotClient().assert({
+        received: getErrorString(expected),
+        test,
+        message,
+        errorMessage,
+      })
     },
   )
   utils.addMethod(
@@ -73,7 +97,16 @@ export const SnapshotPlugin: ChaiPlugin = (chai, utils) => {
       const expected = utils.flag(this, 'object')
       const error = utils.flag(this, 'error')
       const test = utils.flag(this, 'vitest-test')
-      getSnapshotClient().assert(getErrorString(expected), test, message, true, undefined, inlineSnapshot, error)
+      const errorMessage = utils.flag(this, 'message')
+      getSnapshotClient().assert({
+        received: getErrorString(expected),
+        test,
+        message,
+        inlineSnapshot,
+        isInline: true,
+        error,
+        errorMessage,
+      })
     },
   )
 }

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

@@ -12,6 +12,17 @@ export interface Context {
   fullTitle?: string
 }
 
+interface AssertOptions {
+  received: unknown
+  test?: Test
+  message?: string
+  isInline?: boolean
+  properties?: object
+  inlineSnapshot?: string
+  error?: Error
+  errorMessage?: string
+}
+
 export class SnapshotClient {
   test: Test | undefined
   snapshotState: SnapshotState | undefined
@@ -46,7 +57,18 @@ export class SnapshotClient {
     this.test = undefined
   }
 
-  assert(received: unknown, test = this.test, message?: string, isInline = false, properties?: object, inlineSnapshot?: string, error?: Error): void {
+  assert(options: AssertOptions): void {
+    const {
+      test = this.test,
+      message,
+      isInline = false,
+      properties,
+      inlineSnapshot,
+      error,
+      errorMessage,
+    } = options
+    let { received } = options
+
     if (!test)
       throw new Error('Snapshot cannot be used outside of test')
 
@@ -62,7 +84,7 @@ export class SnapshotClient {
           received = deepMergeSnapshot(received, properties)
       }
       catch (err: any) {
-        err.message = 'Snapshot mismatched'
+        err.message = errorMessage || 'Snapshot mismatched'
         throw err
       }
     }
@@ -87,7 +109,7 @@ export class SnapshotClient {
         expect(actual.trim()).equals(expected ? expected.trim() : '')
       }
       catch (error: any) {
-        error.message = `Snapshot \`${key || 'unknown'}\` mismatched`
+        error.message = errorMessage || `Snapshot \`${key || 'unknown'}\` mismatched`
         throw error
       }
     }