diff --git a/handwritten/bigtable/cloudbuild.yaml b/handwritten/bigtable/cloudbuild.yaml
index ef5dbbc30c9b..2fdae9239f34 100644
--- a/handwritten/bigtable/cloudbuild.yaml
+++ b/handwritten/bigtable/cloudbuild.yaml
@@ -5,7 +5,7 @@ steps:
   args:
   - '-c'
   - |
-    cd ../.. && corepack enable pnpm && pnpm install --filter "...{./handwritten/bigtable}"
+    cd ../.. && corepack enable pnpm && pnpm install --filter "./core/test-utils" --filter "...{./handwritten/bigtable}" --ignore-scripts && pnpm --dir core/test-utils run compile && node -e "require('./bin/run-test.cjs').ensureWorkspacePackagesLinked()" && pnpm --filter "...{./handwritten/bigtable}" run prepare --if-present
   dir: 'handwritten/bigtable'
   id: 'install-dependencies'
 
diff --git a/handwritten/bigtable/package.json b/handwritten/bigtable/package.json
index fab4e307fa9b..e04716e47092 100644
--- a/handwritten/bigtable/package.json
+++ b/handwritten/bigtable/package.json
@@ -42,7 +42,7 @@
     "presystem-test": "pnpm run compile",
     "system-test": "node ../../bin/run-test.cjs build/system-test --timeout 600000 --retries 3",
     "pretest": "pnpm run compile",
-    "test": "node ../../bin/run-test.cjs --proxyquire-shim build/test",
+    "test": "node ../../bin/run-test.cjs build/test",
     "test:snap": "SNAPSHOT_UPDATE=1 pnpm test",
     "testproxy": "pnpm run compile && node build/testproxy/index.js",
     "clean": "gts clean",
@@ -93,6 +93,7 @@
     "c8": "^10.1.3",
     "codecov": "^3.8.3",
     "gapic-tools": "^2.0.0",
+    "google-test-utils": "^0.3.0",
     "gts": "^6.0.2",
     "jsdoc": "^4.0.4",
     "jsdoc-fresh": "^6.0.0",
diff --git a/handwritten/bigtable/system-test/client-side-metrics-all-methods.ts b/handwritten/bigtable/system-test/client-side-metrics-all-methods.ts
index d0d8d9ebe49b..d1458e07d1a9 100644
--- a/handwritten/bigtable/system-test/client-side-metrics-all-methods.ts
+++ b/handwritten/bigtable/system-test/client-side-metrics-all-methods.ts
@@ -21,7 +21,7 @@ import {
 import {ResourceMetrics} from '@opentelemetry/sdk-metrics';
 import * as assert from 'assert';
 import {GCPMetricsHandler} from '../src/client-side-metrics/gcp-metrics-handler';
-import * as proxyquire from 'proxyquire';
+import {proxyquire} from 'google-test-utils';
 import {Bigtable, RawFilter} from '../src';
 import {Mutation} from '../src/mutation';
 import {Row} from '../src/row';
diff --git a/handwritten/bigtable/system-test/client-side-metrics.ts b/handwritten/bigtable/system-test/client-side-metrics.ts
index 7a029b37378e..deb3254b6579 100644
--- a/handwritten/bigtable/system-test/client-side-metrics.ts
+++ b/handwritten/bigtable/system-test/client-side-metrics.ts
@@ -21,7 +21,7 @@ import {
 import {ResourceMetrics} from '@opentelemetry/sdk-metrics';
 import * as assert from 'assert';
 import {GCPMetricsHandler} from '../src/client-side-metrics/gcp-metrics-handler';
-import * as proxyquire from 'proxyquire';
+import {proxyquire} from 'google-test-utils';
 import {Bigtable, BigtableOptions} from '../src';
 import {Row} from '../src/row';
 import {
diff --git a/handwritten/bigtable/system-test/gcp-metrics-handler.ts b/handwritten/bigtable/system-test/gcp-metrics-handler.ts
index 2608d6e191b1..a70b449a562c 100644
--- a/handwritten/bigtable/system-test/gcp-metrics-handler.ts
+++ b/handwritten/bigtable/system-test/gcp-metrics-handler.ts
@@ -26,7 +26,7 @@ import {Bigtable} from '../src';
 import {ResourceMetrics} from '@opentelemetry/sdk-metrics';
 import * as assert from 'assert';
 import {ClientOptions} from 'google-gax';
-import * as proxyquire from 'proxyquire';
+import {proxyquire} from 'google-test-utils';
 
 function getHandler(Exporter: typeof CloudMonitoringExporter) {
   const FakeCGPMetricsHandler = proxyquire(
diff --git a/handwritten/bigtable/system-test/read-rows.ts b/handwritten/bigtable/system-test/read-rows.ts
index 15ac57a41298..454f743de83c 100644
--- a/handwritten/bigtable/system-test/read-rows.ts
+++ b/handwritten/bigtable/system-test/read-rows.ts
@@ -26,7 +26,7 @@ import {EventEmitter} from 'events';
 import {Test} from './testTypes';
 import {ServiceError, GrpcClient, GoogleError, CallOptions} from 'google-gax';
 import {PassThrough} from 'stream';
-import * as proxyquire from 'proxyquire';
+import {proxyquire} from 'google-test-utils';
 import {TabularApiSurface} from '../src/tabular-api-surface';
 import * as mocha from 'mocha';
 import {generateId} from './common';
@@ -141,7 +141,10 @@ describe('Bigtable/Table', () => {
             'An error should have been thrown because the client is closed',
           );
         } catch (err: any) {
-          assert.strictEqual(err.message, 'The client has already been closed.');
+          assert.strictEqual(
+            err.message,
+            'The client has already been closed.',
+          );
         }
       } finally {
         const bigtableSecondClient = new Bigtable();
diff --git a/handwritten/bigtable/test/app-profile.ts b/handwritten/bigtable/test/app-profile.ts
index 581c46f98065..3ebd6ec679c7 100644
--- a/handwritten/bigtable/test/app-profile.ts
+++ b/handwritten/bigtable/test/app-profile.ts
@@ -15,7 +15,7 @@
 import * as promisify from '@google-cloud/promisify';
 import * as assert from 'assert';
 import {describe, it, before, beforeEach} from 'mocha';
-import * as proxyquire from 'proxyquire';
+import {proxyquire} from 'google-test-utils';
 import {CallOptions} from 'google-gax';
 
 let promisified = false;
diff --git a/handwritten/bigtable/test/backup.ts b/handwritten/bigtable/test/backup.ts
index 915bcde6bad2..779747a32e2d 100644
--- a/handwritten/bigtable/test/backup.ts
+++ b/handwritten/bigtable/test/backup.ts
@@ -16,7 +16,7 @@ import {PreciseDate} from '@google-cloud/precise-date';
 import * as promisify from '@google-cloud/promisify';
 import * as assert from 'assert';
 import {before, beforeEach, describe, it, afterEach} from 'mocha';
-import * as proxyquire from 'proxyquire';
+import {proxyquire} from 'google-test-utils';
 import * as pumpify from 'pumpify';
 import {ServiceError} from 'google-gax';
 
diff --git a/handwritten/bigtable/test/base64keymap.ts b/handwritten/bigtable/test/base64keymap.ts
index 7446126bff45..d9903a1afe75 100644
--- a/handwritten/bigtable/test/base64keymap.ts
+++ b/handwritten/bigtable/test/base64keymap.ts
@@ -15,7 +15,6 @@
 import * as assert from 'assert';
 import {describe, it, before, beforeEach, afterEach} from 'mocha';
 import Long = require('long');
-import * as proxyquire from 'proxyquire';
 import * as sn from 'sinon';
 
 import {RowStateEnum} from '../src/chunktransformer.js';
diff --git a/handwritten/bigtable/test/chunktransformer.ts b/handwritten/bigtable/test/chunktransformer.ts
index 88e0e313707a..cac31179cb03 100644
--- a/handwritten/bigtable/test/chunktransformer.ts
+++ b/handwritten/bigtable/test/chunktransformer.ts
@@ -15,7 +15,7 @@
 import * as assert from 'assert';
 import {describe, it, before, beforeEach, afterEach} from 'mocha';
 import Long = require('long');
-import * as proxyquire from 'proxyquire';
+import {proxyquire} from 'google-test-utils';
 import * as sn from 'sinon';
 
 import {RowStateEnum} from '../src/chunktransformer.js';
diff --git a/handwritten/bigtable/test/cluster.ts b/handwritten/bigtable/test/cluster.ts
index a1c963cd22f9..a2144ef10318 100644
--- a/handwritten/bigtable/test/cluster.ts
+++ b/handwritten/bigtable/test/cluster.ts
@@ -15,7 +15,7 @@
 import * as promisify from '@google-cloud/promisify';
 import * as assert from 'assert';
 import {before, beforeEach, describe, it} from 'mocha';
-import * as proxyquire from 'proxyquire';
+import {proxyquire} from 'google-test-utils';
 import {PassThrough, Readable} from 'stream';
 import {CallOptions} from 'google-gax';
 import {PreciseDate} from '@google-cloud/precise-date';
diff --git a/handwritten/bigtable/test/executequery.ts b/handwritten/bigtable/test/executequery.ts
index 4d0ea37f205b..ea6168445aed 100644
--- a/handwritten/bigtable/test/executequery.ts
+++ b/handwritten/bigtable/test/executequery.ts
@@ -15,7 +15,7 @@ import * as promisify from '@google-cloud/promisify';
 import * as assert from 'assert';
 import {before, beforeEach, afterEach, describe, it} from 'mocha';
 import * as sinon from 'sinon';
-import * as proxyquire from 'proxyquire';
+import {proxyquire} from 'google-test-utils';
 import {grpc} from 'google-gax';
 import * as inst from '../src/instance';
 import {Bigtable} from '../src';
diff --git a/handwritten/bigtable/test/family.ts b/handwritten/bigtable/test/family.ts
index 4d6b0babc4e2..a4661ca0a57a 100644
--- a/handwritten/bigtable/test/family.ts
+++ b/handwritten/bigtable/test/family.ts
@@ -15,7 +15,7 @@
 import * as promisify from '@google-cloud/promisify';
 import * as assert from 'assert';
 import {before, beforeEach, afterEach, describe, it} from 'mocha';
-import * as proxyquire from 'proxyquire';
+import {proxyquire} from 'google-test-utils';
 import * as sinon from 'sinon';
 import {protos} from '@google-cloud/bigtable-api';
 import google = protos.google;
diff --git a/handwritten/bigtable/test/filter.ts b/handwritten/bigtable/test/filter.ts
index d2dc9fbaed7d..e90d445058d2 100644
--- a/handwritten/bigtable/test/filter.ts
+++ b/handwritten/bigtable/test/filter.ts
@@ -14,7 +14,7 @@
 
 import * as assert from 'assert';
 import {afterEach, before, beforeEach, describe, it} from 'mocha';
-import * as proxyquire from 'proxyquire';
+import {proxyquire} from 'google-test-utils';
 import * as sinon from 'sinon';
 import * as fr from '../src/filter';
 import {Row} from '../src/row';
diff --git a/handwritten/bigtable/test/index.ts b/handwritten/bigtable/test/index.ts
index 361d2527a300..5345ea6dfa0b 100644
--- a/handwritten/bigtable/test/index.ts
+++ b/handwritten/bigtable/test/index.ts
@@ -17,7 +17,7 @@ import * as promisify from '@google-cloud/promisify';
 import * as assert from 'assert';
 import {afterEach, before, beforeEach, describe, it} from 'mocha';
 import * as gax from 'google-gax';
-import * as proxyquire from 'proxyquire';
+import {proxyquire} from 'google-test-utils';
 import * as sn from 'sinon';
 
 import {Cluster} from '../src/cluster.js';
@@ -1216,6 +1216,7 @@ describe('Bigtable', () => {
   });
   describe('close', () => {
     it('should have failed request after close is called', done => {
+      // eslint-disable-next-line promise/catch-or-return, promise/always-return
       bigtable.close().then(() => {
         bigtable.getInstances((err: Error) => {
           if (err) {
diff --git a/handwritten/bigtable/test/instance.ts b/handwritten/bigtable/test/instance.ts
index 47798885b905..e0431a697ae2 100644
--- a/handwritten/bigtable/test/instance.ts
+++ b/handwritten/bigtable/test/instance.ts
@@ -16,7 +16,7 @@ import * as promisify from '@google-cloud/promisify';
 import * as assert from 'assert';
 import {before, beforeEach, afterEach, describe, it} from 'mocha';
 import * as sinon from 'sinon';
-import * as proxyquire from 'proxyquire';
+import {proxyquire} from 'google-test-utils';
 import {ServiceError} from 'google-gax';
 import * as snapshot from 'snap-shot-it';
 import {Readable} from 'stream';
diff --git a/handwritten/bigtable/test/metric-service-client-credentials.ts b/handwritten/bigtable/test/metric-service-client-credentials.ts
index b05caa470f61..ee563ea76e11 100644
--- a/handwritten/bigtable/test/metric-service-client-credentials.ts
+++ b/handwritten/bigtable/test/metric-service-client-credentials.ts
@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-import * as proxyquire from 'proxyquire';
+import {proxyquire} from 'google-test-utils';
 import {ClientOptions, grpc} from 'google-gax';
 import * as assert from 'assert';
 import {MetricServiceClient} from '@google-cloud/monitoring';
diff --git a/handwritten/bigtable/test/metrics-collector/gcp-metrics-handler.ts b/handwritten/bigtable/test/metrics-collector/gcp-metrics-handler.ts
index 6f54951b5551..8c726b111cfa 100644
--- a/handwritten/bigtable/test/metrics-collector/gcp-metrics-handler.ts
+++ b/handwritten/bigtable/test/metrics-collector/gcp-metrics-handler.ts
@@ -30,7 +30,7 @@ import {
 } from '../../test-common/expected-otel-export-input';
 import * as assert from 'assert';
 import {replaceTimestamps} from '../../test-common/replace-timestamps';
-import * as proxyquire from 'proxyquire';
+import {proxyquire} from 'google-test-utils';
 
 /**
  * Cleans a ResourceMetrics object by replacing client UUIDs with a placeholder.
diff --git a/handwritten/bigtable/test/metrics-collector/metrics-collector.ts b/handwritten/bigtable/test/metrics-collector/metrics-collector.ts
index b63bd2b0ba51..92dce755cbcb 100644
--- a/handwritten/bigtable/test/metrics-collector/metrics-collector.ts
+++ b/handwritten/bigtable/test/metrics-collector/metrics-collector.ts
@@ -23,7 +23,7 @@ import {
 import {grpc} from 'google-gax';
 import {expectedRequestsHandled} from '../../test-common/metrics-handler-fixture';
 import * as gax from 'google-gax';
-import * as proxyquire from 'proxyquire';
+import {proxyquire} from 'google-test-utils';
 import {GCPMetricsHandler} from '../../src/client-side-metrics/gcp-metrics-handler';
 import {getProtoPath} from '../../src/utils/protos';
 const protoPath = getProtoPath('google/bigtable/v2/response_params.proto');
diff --git a/handwritten/bigtable/test/row.ts b/handwritten/bigtable/test/row.ts
index ca1f444cfb65..e03bfb56ffc8 100644
--- a/handwritten/bigtable/test/row.ts
+++ b/handwritten/bigtable/test/row.ts
@@ -15,7 +15,7 @@
 import * as promisify from '@google-cloud/promisify';
 import * as assert from 'assert';
 import {afterEach, beforeEach, describe, it} from 'mocha';
-import * as proxyquire from 'proxyquire';
+import {proxyquire} from 'google-test-utils';
 import * as sinon from 'sinon';
 import {Mutation} from '../src/mutation.js';
 import * as rw from '../src/row';
diff --git a/handwritten/bigtable/test/table.ts b/handwritten/bigtable/test/table.ts
index c10e89145d4e..6406de9e25e9 100644
--- a/handwritten/bigtable/test/table.ts
+++ b/handwritten/bigtable/test/table.ts
@@ -15,7 +15,7 @@
 import * as promisify from '@google-cloud/promisify';
 import * as assert from 'assert';
 import {afterEach, before, beforeEach, describe, it} from 'mocha';
-import * as proxyquire from 'proxyquire';
+import {proxyquire} from 'google-test-utils';
 import * as pumpify from 'pumpify';
 import * as sinon from 'sinon';
 import {PassThrough, Writable, Duplex} from 'stream';
diff --git a/handwritten/spanner/cloudbuild.yaml b/handwritten/spanner/cloudbuild.yaml
index 5ac1335ff111..fe987edf9c5f 100644
--- a/handwritten/spanner/cloudbuild.yaml
+++ b/handwritten/spanner/cloudbuild.yaml
@@ -5,7 +5,7 @@ steps:
   args:
   - '-c'
   - |
-    cd ../.. && corepack enable pnpm && pnpm install --filter "...{./handwritten/spanner}"
+    cd ../.. && corepack enable pnpm && pnpm install --filter "./core/test-utils" --filter "...{./handwritten/spanner}" --ignore-scripts && pnpm --dir core/test-utils run compile && node -e "require('./bin/run-test.cjs').ensureWorkspacePackagesLinked()" && pnpm --filter "...{./handwritten/spanner}" run prepare --if-present
   dir: 'handwritten/spanner'
   id: 'install-dependencies'
 
diff --git a/handwritten/spanner/observability-test/batch-transaction.ts b/handwritten/spanner/observability-test/batch-transaction.ts
index f3738c67ecef..3aa215842ec3 100644
--- a/handwritten/spanner/observability-test/batch-transaction.ts
+++ b/handwritten/spanner/observability-test/batch-transaction.ts
@@ -21,7 +21,7 @@ import * as pfy from '@google-cloud/promisify';
 import * as assert from 'assert';
 import {before, after, beforeEach, afterEach, describe, it} from 'mocha';
 import * as extend from 'extend';
-import * as proxyquire from 'proxyquire';
+import {proxyquire} from 'google-test-utils';
 import * as sinon from 'sinon';
 const {
   AlwaysOnSampler,
diff --git a/handwritten/spanner/observability-test/database.ts b/handwritten/spanner/observability-test/database.ts
index 1c9410242d33..1b3a3e23df4b 100644
--- a/handwritten/spanner/observability-test/database.ts
+++ b/handwritten/spanner/observability-test/database.ts
@@ -30,7 +30,7 @@ import {
 } from '../src/transaction';
 import {util} from '@google-cloud/common';
 import {Transform} from 'stream';
-import * as proxyquire from 'proxyquire';
+import {proxyquire} from 'google-test-utils';
 import * as sinon from 'sinon';
 const {SpanStatusCode} = require('@opentelemetry/api');
 const {
diff --git a/handwritten/spanner/observability-test/helper.ts b/handwritten/spanner/observability-test/helper.ts
index fc610a4f912f..45be0d2c891a 100644
--- a/handwritten/spanner/observability-test/helper.ts
+++ b/handwritten/spanner/observability-test/helper.ts
@@ -43,6 +43,7 @@ export const cacheSessionEvents = ['Cache hit: has usable multiplexed session'];
  * and referring to context causes type/value collision errors.
  */
 export function setGlobalContextManager(manager: ContextManager) {
+  context.disable();
   if (typeof manager.enable === 'function') {
     manager.enable();
   }
diff --git a/handwritten/spanner/observability-test/spanner.ts b/handwritten/spanner/observability-test/spanner.ts
index a262314b2f79..8d9854f8fb52 100644
--- a/handwritten/spanner/observability-test/spanner.ts
+++ b/handwritten/spanner/observability-test/spanner.ts
@@ -188,6 +188,7 @@ describe('EndToEnd', async () => {
   const database = instance.database('database');
 
   beforeEach(async () => {
+    setGlobalContextManager(contextManager);
     // To deflake expectations of session creation, let's
     // issue out a warm-up request request that'll ensure
     // that the MultiplexedSession is created deterministically.
diff --git a/handwritten/spanner/observability-test/table.ts b/handwritten/spanner/observability-test/table.ts
index 36257b34e875..5f76ba14bf59 100644
--- a/handwritten/spanner/observability-test/table.ts
+++ b/handwritten/spanner/observability-test/table.ts
@@ -18,7 +18,7 @@ import * as pfy from '@google-cloud/promisify';
 import * as assert from 'assert';
 import {before, beforeEach, afterEach, describe, it} from 'mocha';
 import * as extend from 'extend';
-import * as proxyquire from 'proxyquire';
+import {proxyquire} from 'google-test-utils';
 import * as sinon from 'sinon';
 import * as through from 'through2';
 
diff --git a/handwritten/spanner/observability-test/transaction.ts b/handwritten/spanner/observability-test/transaction.ts
index 126b52141b8c..642e1066b1b3 100644
--- a/handwritten/spanner/observability-test/transaction.ts
+++ b/handwritten/spanner/observability-test/transaction.ts
@@ -17,7 +17,7 @@
 import * as assert from 'assert';
 import {before, beforeEach, afterEach, describe, it} from 'mocha';
 import {EventEmitter} from 'events';
-import * as proxyquire from 'proxyquire';
+import {proxyquire} from 'google-test-utils';
 import * as sinon from 'sinon';
 
 import {codec} from '../src/codec';
diff --git a/handwritten/spanner/package.json b/handwritten/spanner/package.json
index e07b4ae6b71c..04702a7dc5c6 100644
--- a/handwritten/spanner/package.json
+++ b/handwritten/spanner/package.json
@@ -35,9 +35,9 @@
     "predocs": "pnpm run compile",
     "lint": "gts check",
     "system-test": "node ../../bin/run-test.cjs build/system-test --timeout 1600000",
-    "observability-test": "node ../../bin/run-test.cjs --proxyquire-shim build/observability-test --timeout 1600000",
+    "observability-test": "node ../../bin/run-test.cjs build/observability-test --timeout 1600000",
     "cleanup": "node ../../bin/run-test.cjs scripts/cleanup.js --timeout 30000",
-    "test": "node ../../bin/run-test.cjs --proxyquire-shim build/test build/test/common build/observability-test",
+    "test": "node ../../bin/run-test.cjs build/test build/test/common build/observability-test",
     "ycsb": "node ./benchmark/ycsb.js  run -P ./benchmark/workloada -p table=usertable -p cloudspanner.instance=ycsb-instance -p operationcount=100 -p cloudspanner.database=ycsb",
     "fix": "gts fix",
     "clean": "gts clean",
@@ -107,7 +107,7 @@
     "dedent": "^1.5.3",
     "execa": "^5.0.0",
     "gapic-tools": "^2.0.0",
-    "google-test-utils": "^0.2.0",
+    "google-test-utils": "^0.3.0",
     "grpc-health-check": "^2.1.0",
     "gts": "^6.0.2",
     "jsdoc": "^4.0.4",
diff --git a/handwritten/spanner/test/backup.ts b/handwritten/spanner/test/backup.ts
index f52acc976b1b..9ef283045d36 100644
--- a/handwritten/spanner/test/backup.ts
+++ b/handwritten/spanner/test/backup.ts
@@ -17,7 +17,7 @@
 
 import * as assert from 'assert';
 import {EventEmitter} from 'events';
-import * as proxyquire from 'proxyquire';
+import {proxyquire} from 'google-test-utils';
 import * as sinon from 'sinon';
 import {util} from '@google-cloud/common';
 import * as pfy from '@google-cloud/promisify';
diff --git a/handwritten/spanner/test/batch-transaction.ts b/handwritten/spanner/test/batch-transaction.ts
index 990bee6bb8bd..d9945b34d615 100644
--- a/handwritten/spanner/test/batch-transaction.ts
+++ b/handwritten/spanner/test/batch-transaction.ts
@@ -20,7 +20,7 @@ import {util} from '@google-cloud/common';
 import * as pfy from '@google-cloud/promisify';
 import * as assert from 'assert';
 import {before, beforeEach, afterEach, describe, it} from 'mocha';
-import * as proxyquire from 'proxyquire';
+import {proxyquire} from 'google-test-utils';
 import * as sinon from 'sinon';
 
 import {Session, Database, Spanner, protos} from '../src';
diff --git a/handwritten/spanner/test/common/service-object.ts b/handwritten/spanner/test/common/service-object.ts
index 7e5544eb8e95..208c3f148d39 100644
--- a/handwritten/spanner/test/common/service-object.ts
+++ b/handwritten/spanner/test/common/service-object.ts
@@ -19,7 +19,7 @@ import * as pfy from '@google-cloud/promisify';
 import * as assert from 'assert';
 import {before, beforeEach, describe, it} from 'mocha';
 import * as extend from 'extend';
-import * as proxyquire from 'proxyquire';
+import {proxyquire} from 'google-test-utils';
 
 let promisified = false;
 const fakePfy = Object.assign({}, pfy, {
diff --git a/handwritten/spanner/test/common/service.ts b/handwritten/spanner/test/common/service.ts
index 11ea01a9820a..05fc2d0d0a58 100644
--- a/handwritten/spanner/test/common/service.ts
+++ b/handwritten/spanner/test/common/service.ts
@@ -20,7 +20,7 @@ import {before, beforeEach, after, afterEach, describe, it} from 'mocha';
 import * as duplexify from 'duplexify';
 import * as extend from 'extend';
 import {grpc, GrpcClient} from 'google-gax';
-import * as proxyquire from 'proxyquire';
+import {proxyquire} from 'google-test-utils';
 import * as retryRequest from 'retry-request';
 import * as sn from 'sinon';
 import {PassThrough} from 'stream';
diff --git a/handwritten/spanner/test/database.ts b/handwritten/spanner/test/database.ts
index ea94628136e6..d5b66fae4bce 100644
--- a/handwritten/spanner/test/database.ts
+++ b/handwritten/spanner/test/database.ts
@@ -21,7 +21,7 @@ import {before, beforeEach, afterEach, describe, it} from 'mocha';
 import {EventEmitter} from 'events';
 import * as extend from 'extend';
 import {ApiError, util} from '@google-cloud/common';
-import * as proxyquire from 'proxyquire';
+import {proxyquire} from 'google-test-utils';
 import * as sinon from 'sinon';
 import {Transform, Duplex} from 'stream';
 import * as through from 'through2';
diff --git a/handwritten/spanner/test/index.ts b/handwritten/spanner/test/index.ts
index 384eb8b5c440..ea9fa0c6ca9a 100644
--- a/handwritten/spanner/test/index.ts
+++ b/handwritten/spanner/test/index.ts
@@ -20,7 +20,7 @@ import * as assert from 'assert';
 import {before, beforeEach, afterEach, describe, it} from 'mocha';
 import * as extend from 'extend';
 import * as path from 'path';
-import * as proxyquire from 'proxyquire';
+import {proxyquire} from 'google-test-utils';
 import * as through from 'through2';
 import {util} from '@google-cloud/common';
 import {PreciseDate} from '@google-cloud/precise-date';
diff --git a/handwritten/spanner/test/instance-config.ts b/handwritten/spanner/test/instance-config.ts
index dd050be447f0..b755ff8033b4 100644
--- a/handwritten/spanner/test/instance-config.ts
+++ b/handwritten/spanner/test/instance-config.ts
@@ -18,7 +18,7 @@
 import * as assert from 'assert';
 import {before, beforeEach, afterEach, describe, it} from 'mocha';
 import {grpc} from 'google-gax';
-import * as proxyquire from 'proxyquire';
+import {proxyquire} from 'google-test-utils';
 import * as pfy from '@google-cloud/promisify';
 import * as sinon from 'sinon';
 
diff --git a/handwritten/spanner/test/instance.ts b/handwritten/spanner/test/instance.ts
index f816e2fa0d15..263d9bb9621f 100644
--- a/handwritten/spanner/test/instance.ts
+++ b/handwritten/spanner/test/instance.ts
@@ -20,7 +20,7 @@ import * as assert from 'assert';
 import {before, beforeEach, afterEach, describe, it} from 'mocha';
 import {ApiError} from '@google-cloud/common';
 import {grpc} from 'google-gax';
-import * as proxyquire from 'proxyquire';
+import {proxyquire} from 'google-test-utils';
 import * as pfy from '@google-cloud/promisify';
 import * as sinon from 'sinon';
 import snakeCase = require('lodash.snakecase');
diff --git a/handwritten/spanner/test/partial-result-stream.ts b/handwritten/spanner/test/partial-result-stream.ts
index 4d8560be7593..05d2fa8e1a45 100644
--- a/handwritten/spanner/test/partial-result-stream.ts
+++ b/handwritten/spanner/test/partial-result-stream.ts
@@ -19,7 +19,6 @@ import {before, beforeEach, afterEach, describe, it} from 'mocha';
 // eslint-disable-next-line @typescript-eslint/no-var-requires
 // eslint-disable-next-line @typescript-eslint/no-var-requires
 const concat = require('concat-stream');
-import * as proxyquire from 'proxyquire';
 import * as sinon from 'sinon';
 import {Transform, finished} from 'stream';
 import * as through from 'through2';
@@ -28,7 +27,7 @@ import {codec} from '../src/codec';
 import {PreciseDate} from '@google-cloud/precise-date';
 import * as prs from '../src/partial-result-stream';
 import {grpc} from 'google-gax';
-import {assertArraySubclassStrictEqual} from 'google-test-utils';
+import {assertArraySubclassStrictEqual, proxyquire} from 'google-test-utils';
 import {Row} from '../src/partial-result-stream';
 
 function toRawValue(value: any): any {
diff --git a/handwritten/spanner/test/session.ts b/handwritten/spanner/test/session.ts
index 60e2de6845a6..6e8e48c36afc 100644
--- a/handwritten/spanner/test/session.ts
+++ b/handwritten/spanner/test/session.ts
@@ -19,7 +19,7 @@
 import * as pfy from '@google-cloud/promisify';
 import * as assert from 'assert';
 import {before, beforeEach, describe, it} from 'mocha';
-import * as proxyquire from 'proxyquire';
+import {proxyquire} from 'google-test-utils';
 import {
   CLOUD_RESOURCE_HEADER,
   LEADER_AWARE_ROUTING_HEADER,
diff --git a/handwritten/spanner/test/table.ts b/handwritten/spanner/test/table.ts
index 199d456215ba..b492b7a8d7a2 100644
--- a/handwritten/spanner/test/table.ts
+++ b/handwritten/spanner/test/table.ts
@@ -17,7 +17,7 @@
 import * as pfy from '@google-cloud/promisify';
 import * as assert from 'assert';
 import {before, beforeEach, afterEach, describe, it} from 'mocha';
-import * as proxyquire from 'proxyquire';
+import {proxyquire} from 'google-test-utils';
 import * as sinon from 'sinon';
 import {Transform} from 'stream';
 import * as through from 'through2';
diff --git a/handwritten/spanner/test/transaction-runner.ts b/handwritten/spanner/test/transaction-runner.ts
index 9a2bd818b313..d258340da1d3 100644
--- a/handwritten/spanner/test/transaction-runner.ts
+++ b/handwritten/spanner/test/transaction-runner.ts
@@ -18,7 +18,7 @@ import * as assert from 'assert';
 import {before, beforeEach, afterEach, describe, it} from 'mocha';
 import {EventEmitter} from 'events';
 import {grpc} from 'google-gax';
-import * as proxyquire from 'proxyquire';
+import {proxyquire} from 'google-test-utils';
 import * as sinon from 'sinon';
 import * as through from 'through2';
 import {RunTransactionOptions} from '../src/transaction-runner';
@@ -329,6 +329,7 @@ describe('TransactionRunner', () => {
 
         runner
           .run()
+          // eslint-disable-next-line promise/always-return
           .then(() => {
             done(new Error('missing expected DEADLINE_EXCEEDED error'));
           })
diff --git a/handwritten/spanner/test/transaction.ts b/handwritten/spanner/test/transaction.ts
index 5e5e13ef7590..55706e14605c 100644
--- a/handwritten/spanner/test/transaction.ts
+++ b/handwritten/spanner/test/transaction.ts
@@ -19,7 +19,7 @@ import * as assert from 'assert';
 import {before, beforeEach, afterEach, describe, it} from 'mocha';
 import {EventEmitter} from 'events';
 import {common as p} from 'protobufjs';
-import * as proxyquire from 'proxyquire';
+import {proxyquire} from 'google-test-utils';
 import * as sinon from 'sinon';
 
 import {codec} from '../src/codec';
diff --git a/handwritten/storage/cloudbuild.yaml b/handwritten/storage/cloudbuild.yaml
index c0d5e374ea4a..57e5f1eb1536 100644
--- a/handwritten/storage/cloudbuild.yaml
+++ b/handwritten/storage/cloudbuild.yaml
@@ -5,7 +5,7 @@ steps:
   args:
   - '-c'
   - |
-    cd ../.. && corepack enable pnpm && pnpm install --filter "...{./handwritten/storage}"
+    cd ../.. && corepack enable pnpm && pnpm install --filter "./core/test-utils" --filter "...{./handwritten/storage}" --ignore-scripts && pnpm --dir core/test-utils run compile && node -e "require('./bin/run-test.cjs').ensureWorkspacePackagesLinked()" && pnpm --filter "...{./handwritten/storage}" run prepare --if-present
   dir: 'handwritten/storage'
   id: 'install-dependencies'
 
diff --git a/handwritten/storage/package.json b/handwritten/storage/package.json
index 461391690a21..ee196e30138c 100644
--- a/handwritten/storage/package.json
+++ b/handwritten/storage/package.json
@@ -71,7 +71,7 @@
     "pretest": "pnpm run compile --sourceMap",
     "system-test:esm": "mkdir -p $HOME/.config && node ../../bin/run-test.cjs --no-parallel build/esm/system-test --timeout 600000 --exit",
     "system-test": "mkdir -p $HOME/.config && node ../../bin/run-test.cjs --no-parallel build/cjs/system-test --timeout 600000 --exit",
-    "test": "cross-env NODE_OPTIONS=\"--require ./scripts/preload-yargs.cjs --no-deprecation\" node ../../bin/run-test.cjs --proxyquire-shim build/cjs/test"
+    "test": "cross-env NODE_OPTIONS=\"--require ./scripts/preload-yargs.cjs --no-deprecation\" node ../../bin/run-test.cjs build/cjs/test"
   },
   "dependencies": {
     "@google-cloud/paginator": "^7.0.1",
@@ -110,6 +110,7 @@
     "cross-env": "^7.0.3",
     "form-data": "^4.0.4",
     "gapic-tools": "^2.0.1",
+    "google-test-utils": "^0.3.0",
     "gts": "^5.0.0",
     "jsdoc": "^4.0.4",
     "jsdoc-fresh": "^6.0.0",
diff --git a/handwritten/storage/test/acl.ts b/handwritten/storage/test/acl.ts
index 5c1d73e25ae0..ba6c7d876ceb 100644
--- a/handwritten/storage/test/acl.ts
+++ b/handwritten/storage/test/acl.ts
@@ -15,7 +15,7 @@
 import {DecorateRequestOptions, util} from '../src/nodejs-common/index.js';
 import assert from 'assert';
 import {describe, it, before, beforeEach} from 'mocha';
-import proxyquire from 'proxyquire';
+import {proxyquire} from 'google-test-utils';
 import {Storage} from '../src/storage.js';
 
 // eslint-disable-next-line @typescript-eslint/no-explicit-any
diff --git a/handwritten/storage/test/bucket.ts b/handwritten/storage/test/bucket.ts
index 09928da7aab4..91eafa1e2263 100644
--- a/handwritten/storage/test/bucket.ts
+++ b/handwritten/storage/test/bucket.ts
@@ -26,7 +26,7 @@ import {describe, it, before, beforeEach, after, afterEach} from 'mocha';
 import mime from 'mime';
 import pLimit from 'p-limit';
 import * as path from 'path';
-import proxyquire from 'proxyquire';
+import {proxyquire} from 'google-test-utils';
 
 import * as stream from 'stream';
 import {Bucket, Channel, Notification, CRC32C} from '../src/index.js';
diff --git a/handwritten/storage/test/channel.ts b/handwritten/storage/test/channel.ts
index e70272f20453..b9c5039d1599 100644
--- a/handwritten/storage/test/channel.ts
+++ b/handwritten/storage/test/channel.ts
@@ -24,7 +24,7 @@ import {
 } from '../src/nodejs-common/index.js';
 import assert from 'assert';
 import {describe, it, before, beforeEach} from 'mocha';
-import proxyquire from 'proxyquire';
+import {proxyquire} from 'google-test-utils';
 
 let promisified = false;
 const fakePromisify = {
diff --git a/handwritten/storage/test/file.ts b/handwritten/storage/test/file.ts
index 938e8e317bba..962bf4dbad78 100644
--- a/handwritten/storage/test/file.ts
+++ b/handwritten/storage/test/file.ts
@@ -36,7 +36,7 @@ import * as crypto from 'crypto';
 import duplexify from 'duplexify';
 import * as fs from 'fs';
 import * as path from 'path';
-import proxyquire from 'proxyquire';
+import {proxyquire} from 'google-test-utils';
 import * as resumableUpload from '../src/resumable-upload.js';
 import * as sinon from 'sinon';
 import * as tmp from 'tmp';
diff --git a/handwritten/storage/test/headers.ts b/handwritten/storage/test/headers.ts
index b786ae54d4e0..fc1f437c4a97 100644
--- a/handwritten/storage/test/headers.ts
+++ b/handwritten/storage/test/headers.ts
@@ -14,7 +14,7 @@
 
 import * as assert from 'assert';
 import {describe, it} from 'mocha';
-import proxyquire from 'proxyquire';
+import {proxyquire} from 'google-test-utils';
 
 const error = Error('not implemented');
 
diff --git a/handwritten/storage/test/hmacKey.ts b/handwritten/storage/test/hmacKey.ts
index b67da92d7233..f8a3da7e723b 100644
--- a/handwritten/storage/test/hmacKey.ts
+++ b/handwritten/storage/test/hmacKey.ts
@@ -13,7 +13,7 @@
 // limitations under the License.
 
 import * as sinon from 'sinon';
-import proxyquire from 'proxyquire';
+import {proxyquire} from 'google-test-utils';
 import assert from 'assert';
 import {describe, it, beforeEach, afterEach} from 'mocha';
 import {util, ServiceObject} from '../src/nodejs-common/index.js';
diff --git a/handwritten/storage/test/iam.ts b/handwritten/storage/test/iam.ts
index a037e77b0a46..d4b8440faf89 100644
--- a/handwritten/storage/test/iam.ts
+++ b/handwritten/storage/test/iam.ts
@@ -15,7 +15,7 @@
 import {DecorateRequestOptions, util} from '../src/nodejs-common/index.js';
 import assert from 'assert';
 import {describe, it, before, beforeEach} from 'mocha';
-import proxyquire from 'proxyquire';
+import {proxyquire} from 'google-test-utils';
 import {IAMExceptionMessages} from '../src/iam.js';
 
 describe('storage/iam', () => {
diff --git a/handwritten/storage/test/index.ts b/handwritten/storage/test/index.ts
index f615cbeb1ffa..d3d8360fab7b 100644
--- a/handwritten/storage/test/index.ts
+++ b/handwritten/storage/test/index.ts
@@ -22,7 +22,7 @@ import {
 import {PromisifyAllOptions} from '@google-cloud/promisify';
 import assert from 'assert';
 import {describe, it, before, beforeEach, after, afterEach} from 'mocha';
-import proxyquire from 'proxyquire';
+import {proxyquire} from 'google-test-utils';
 // eslint-disable-next-line @typescript-eslint/no-unused-vars
 import {Bucket, CRC32C_DEFAULT_VALIDATOR_GENERATOR} from '../src/index.js';
 import {GetFilesOptions} from '../src/bucket.js';
diff --git a/handwritten/storage/test/nodejs-common/service-object.ts b/handwritten/storage/test/nodejs-common/service-object.ts
index ac22a62dbdcf..159949ebe6e7 100644
--- a/handwritten/storage/test/nodejs-common/service-object.ts
+++ b/handwritten/storage/test/nodejs-common/service-object.ts
@@ -21,7 +21,7 @@ import {
 } from '@google-cloud/promisify';
 import assert from 'assert';
 import {describe, it, beforeEach, afterEach} from 'mocha';
-import proxyquire from 'proxyquire';
+import {proxyquire} from 'google-test-utils';
 import type {
   OptionsWithUri,
   Request as TeenyRequest,
diff --git a/handwritten/storage/test/nodejs-common/service.ts b/handwritten/storage/test/nodejs-common/service.ts
index f785a1315793..131dcbf4122f 100644
--- a/handwritten/storage/test/nodejs-common/service.ts
+++ b/handwritten/storage/test/nodejs-common/service.ts
@@ -16,7 +16,7 @@
 
 import assert from 'assert';
 import {describe, it, before, beforeEach, after} from 'mocha';
-import proxyquire from 'proxyquire';
+import {proxyquire} from 'google-test-utils';
 import {Request} from 'teeny-request';
 import {AuthClient, GoogleAuth, OAuth2Client} from 'google-auth-library';
 
diff --git a/handwritten/storage/test/nodejs-common/util.ts b/handwritten/storage/test/nodejs-common/util.ts
index d7ebc515c3fb..e764734227e7 100644
--- a/handwritten/storage/test/nodejs-common/util.ts
+++ b/handwritten/storage/test/nodejs-common/util.ts
@@ -27,7 +27,7 @@ import {
   OAuth2Client,
 } from 'google-auth-library';
 import * as nock from 'nock';
-import proxyquire from 'proxyquire';
+import {proxyquire} from 'google-test-utils';
 import retryRequest from 'retry-request';
 import * as sinon from 'sinon';
 import * as stream from 'stream';
diff --git a/handwritten/storage/test/notification.ts b/handwritten/storage/test/notification.ts
index fe396dcb512a..f562ec14fd92 100644
--- a/handwritten/storage/test/notification.ts
+++ b/handwritten/storage/test/notification.ts
@@ -21,7 +21,7 @@ import {
 } from '../src/nodejs-common/index.js';
 import assert from 'assert';
 import {describe, it, before, beforeEach} from 'mocha';
-import proxyquire from 'proxyquire';
+import {proxyquire} from 'google-test-utils';
 
 import {Bucket} from '../src/index.js';
 
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index d3e796667663..5cc7e10574bf 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -1934,6 +1934,9 @@ importers:
       gapic-tools:
         specifier: ^2.0.0
         version: 2.0.1(protobufjs@8.8.0)
+      google-test-utils:
+        specifier: ^0.3.0
+        version: 0.3.0
       gts:
         specifier: ^6.0.2
         version: 6.0.2(typescript@5.9.3)
@@ -3217,8 +3220,8 @@ importers:
         specifier: ^2.0.0
         version: 2.0.1(protobufjs@7.5.9)
       google-test-utils:
-        specifier: ^0.2.0
-        version: 0.2.0
+        specifier: ^0.3.0
+        version: 0.3.0
       grpc-health-check:
         specifier: ^2.1.0
         version: 2.1.0
@@ -3435,6 +3438,9 @@ importers:
       gapic-tools:
         specifier: ^2.0.1
         version: 2.0.1(protobufjs@8.8.0)
+      google-test-utils:
+        specifier: ^0.3.0
+        version: 0.3.0
       gts:
         specifier: ^5.0.0
         version: 5.3.1(typescript@5.9.3)
@@ -20775,10 +20781,6 @@ packages:
     resolution: {integrity: sha512-fbvUWVNh3rKGlVFWwlUNF7Sk1Tah0a89q02rLTXsWjbKKHGeuURAa8tl9rvu5TyWny1YiSIo5eDqF260Tai6vQ==}
     engines: {node: '>=22'}
 
-  google-test-utils@0.2.0:
-    resolution: {integrity: sha512-OP7B5iS65EjAlRctfq3uUdGWXN5AvIGRYQSx5luCVqkfh3uaGvVzuY1y3hCyxLk6MGf5DYkJ3rZxgJ6JsMmSog==}
-    engines: {node: '>=22'}
-
   google-test-utils@0.3.0:
     resolution: {integrity: sha512-atGLcriC2MS6gWCJnCNrxLqYh4Xs5WkgaS9+lwxF/3rZdzt5eFv/Bc2VIeCCl5DGzGP3So8dj5f7pfBUNRhzXw==}
     engines: {node: '>=22'}
@@ -32065,8 +32067,6 @@ snapshots:
       protobufjs: 7.5.9
       walkdir: 0.4.1
 
-  google-test-utils@0.2.0: {}
-
   google-test-utils@0.3.0: {}
 
   googleapis-common@4.4.3(encoding@0.1.13):