Improve snapshot error messages

Author: dgieselaar

packages/kbn-test/src/functional_test_runner/lib/snapshots/decorate_snapshot_ui.ts

@@ -24,7 +24,6 @@ import {
   addSerializer,
 } from 'jest-snapshot';
 import path from 'path';
-import expect from '@kbn/expect';
 import prettier from 'prettier';
 import babelTraverse from '@babel/traverse';
 import { flatten, once } from 'lodash';
@@ -227,7 +226,9 @@ function expectToMatchSnapshot(snapshotContext: SnapshotContext, received: any)
   const matcher = toMatchSnapshot.bind(snapshotContext as any);
   const result = matcher(received);
 
-  expect(result.pass).to.eql(true, result.message());
+  if (!result.pass) {
+    throw new Error(result.message());
+  }
 }
 
 function expectToMatchInlineSnapshot(
@@ -239,5 +240,7 @@ function expectToMatchInlineSnapshot(
 
   const result = arguments.length === 2 ? matcher(received) : matcher(received, _actual);
 
-  expect(result.pass).to.eql(true, result.message());
+  if (!result.pass) {
+    throw new Error(result.message());
+  }
 }