diff --git a/packages/realm-server/tests/realm-endpoints/cancel-indexing-job-test.ts b/packages/realm-server/tests/realm-endpoints/cancel-indexing-job-test.ts
index e85d27f5810..f500e5ce3b9 100644
--- a/packages/realm-server/tests/realm-endpoints/cancel-indexing-job-test.ts
+++ b/packages/realm-server/tests/realm-endpoints/cancel-indexing-job-test.ts
@@ -36,6 +36,7 @@ module(`realm-endpoints/${basename(__filename)}`, function () {
       }
 
       setupPermissionedRealmCached(hooks, {
+        fixture: 'blank',
         permissions: {
           writer: ['read', 'write'],
           reader: ['read'],
diff --git a/packages/realm-server/tests/realm-endpoints/dependencies-test.ts b/packages/realm-server/tests/realm-endpoints/dependencies-test.ts
index 7150953624d..e8616d00c9c 100644
--- a/packages/realm-server/tests/realm-endpoints/dependencies-test.ts
+++ b/packages/realm-server/tests/realm-endpoints/dependencies-test.ts
@@ -29,6 +29,7 @@ module(`realm-endpoints/${basename(__filename)}`, function (hooks) {
   });
 
   setupPermissionedRealmCached(hooks, {
+    fixture: 'blank',
     permissions: {
       '*': ['read'],
     },
diff --git a/packages/realm-server/tests/realm-endpoints/directory-test.ts b/packages/realm-server/tests/realm-endpoints/directory-test.ts
index 49c789728ae..70bea72f2ff 100644
--- a/packages/realm-server/tests/realm-endpoints/directory-test.ts
+++ b/packages/realm-server/tests/realm-endpoints/directory-test.ts
@@ -1,8 +1,6 @@
 import { module, test } from 'qunit';
 import type { Test, SuperTest } from 'supertest';
-import { join, basename } from 'path';
-import { dirSync, type DirResult } from 'tmp';
-import { copySync } from 'fs-extra';
+import { basename } from 'path';
 import type { Realm } from '@cardstack/runtime-common';
 import {
   setupPermissionedRealmCached,
@@ -12,28 +10,21 @@ import {
 import '@cardstack/runtime-common/helpers/code-equality-assertion';
 
 module(`realm-endpoints/${basename(__filename)}`, function () {
-  module('Realm-specific Endpoints | GET directory path', function (hooks) {
+  module('Realm-specific Endpoints | GET directory path', function () {
     let testRealm: Realm;
     let request: SuperTest<Test>;
-    let dir: DirResult;
-
-    hooks.beforeEach(async function () {
-      dir = dirSync();
-      copySync(join(__dirname, '..', 'cards'), dir.name);
-    });
 
     function onRealmSetup(args: {
       testRealm: Realm;
       request: SuperTest<Test>;
-      dir: DirResult;
     }) {
       testRealm = args.testRealm;
       request = args.request;
-      dir = args.dir;
     }
 
     module('public readable realm', function (hooks) {
       setupPermissionedRealmCached(hooks, {
+        fixture: 'realistic',
         permissions: {
           '*': ['read'],
         },
@@ -102,6 +93,7 @@ module(`realm-endpoints/${basename(__filename)}`, function () {
 
     module('permissioned realm', function (hooks) {
       setupPermissionedRealmCached(hooks, {
+        fixture: 'realistic',
         permissions: {
           john: ['read'],
           '@node-test_realm:localhost': ['read', 'realm-owner'],
diff --git a/packages/realm-server/tests/realm-endpoints/info-test.ts b/packages/realm-server/tests/realm-endpoints/info-test.ts
index 841a52b2f70..fee220e9e2d 100644
--- a/packages/realm-server/tests/realm-endpoints/info-test.ts
+++ b/packages/realm-server/tests/realm-endpoints/info-test.ts
@@ -1,9 +1,7 @@
 import { module, test } from 'qunit';
 import type { Test, SuperTest } from 'supertest';
-import { join, basename } from 'path';
+import { basename } from 'path';
 import type { Server } from 'http';
-import { dirSync, type DirResult } from 'tmp';
-import { copySync } from 'fs-extra';
 import type { Realm } from '@cardstack/runtime-common';
 import {
   setupPermissionedRealmCached,
@@ -21,25 +19,17 @@ module(`realm-endpoints/${basename(__filename)}`, function () {
     let testRealm: Realm;
     let testRealmHttpServer: Server;
     let request: SuperTest<Test>;
-    let dir: DirResult;
 
     function onRealmSetup(args: {
       testRealm: Realm;
       testRealmHttpServer: Server;
       request: SuperTest<Test>;
-      dir: DirResult;
     }) {
       testRealm = args.testRealm;
       testRealmHttpServer = args.testRealmHttpServer;
       request = args.request;
-      dir = args.dir;
     }
 
-    hooks.beforeEach(async function () {
-      dir = dirSync();
-      copySync(join(__dirname, '..', 'cards'), dir.name);
-    });
-
     hooks.afterEach(async function () {
       await closeServer(testRealmHttpServer);
       resetCatalogRealms();
@@ -47,6 +37,7 @@ module(`realm-endpoints/${basename(__filename)}`, function () {
 
     module('public readable realm', function (hooks) {
       setupPermissionedRealmCached(hooks, {
+        fixture: 'realistic',
         permissions: {
           '*': ['read'],
         },
@@ -91,6 +82,7 @@ module(`realm-endpoints/${basename(__filename)}`, function () {
 
     module('permissioned realm', function (hooks) {
       setupPermissionedRealmCached(hooks, {
+        fixture: 'realistic',
         permissions: {
           '@node-test_realm:localhost': ['read', 'realm-owner'],
         },
@@ -163,6 +155,7 @@ module(`realm-endpoints/${basename(__filename)}`, function () {
       'shared realm because there is `users` permission',
       function (hooks) {
         setupPermissionedRealmCached(hooks, {
+          fixture: 'realistic',
           permissions: {
             users: ['read'],
             '@node-test_realm:localhost': ['read', 'realm-owner'],
@@ -204,6 +197,7 @@ module(`realm-endpoints/${basename(__filename)}`, function () {
 
     module('shared realm because there are multiple users', function (hooks) {
       setupPermissionedRealmCached(hooks, {
+        fixture: 'realistic',
         permissions: {
           bob: ['read'],
           jane: ['read'],
diff --git a/packages/realm-server/tests/realm-endpoints/lint-test.ts b/packages/realm-server/tests/realm-endpoints/lint-test.ts
index 6a099a9ef26..a0934b8d7e9 100644
--- a/packages/realm-server/tests/realm-endpoints/lint-test.ts
+++ b/packages/realm-server/tests/realm-endpoints/lint-test.ts
@@ -26,6 +26,7 @@ module(`realm-endpoints/${basename(__filename)}`, function () {
     }
 
     setupPermissionedRealmCached(hooks, {
+      fixture: 'blank',
       permissions: {
         john: ['read', 'write'],
         '@node-test_realm:localhost': ['read', 'realm-owner'],
diff --git a/packages/realm-server/tests/realm-endpoints/mtimes-test.ts b/packages/realm-server/tests/realm-endpoints/mtimes-test.ts
index 80feb92620e..7035151d31b 100644
--- a/packages/realm-server/tests/realm-endpoints/mtimes-test.ts
+++ b/packages/realm-server/tests/realm-endpoints/mtimes-test.ts
@@ -28,6 +28,7 @@ module(`realm-endpoints/${basename(__filename)}`, function () {
     }
 
     setupPermissionedRealmCached(hooks, {
+      fixture: 'blank',
       permissions: {
         mary: ['read'],
         '@node-test_realm:localhost': ['read', 'realm-owner'],
diff --git a/packages/realm-server/tests/realm-endpoints/permissions-test.ts b/packages/realm-server/tests/realm-endpoints/permissions-test.ts
index a034b0a0c6e..0de2589888e 100644
--- a/packages/realm-server/tests/realm-endpoints/permissions-test.ts
+++ b/packages/realm-server/tests/realm-endpoints/permissions-test.ts
@@ -1,8 +1,6 @@
 import { module, test } from 'qunit';
 import type { Test, SuperTest } from 'supertest';
-import { join, basename } from 'path';
-import { dirSync, type DirResult } from 'tmp';
-import { copySync } from 'fs-extra';
+import { basename } from 'path';
 import type { Realm } from '@cardstack/runtime-common';
 import { fetchRealmPermissions } from '@cardstack/runtime-common';
 import {
@@ -15,32 +13,24 @@ import '@cardstack/runtime-common/helpers/code-equality-assertion';
 import type { PgAdapter } from '@cardstack/postgres';
 
 module(`realm-endpoints/${basename(__filename)}`, function () {
-  module('Realm-specific Endpoints | _permissions', function (hooks) {
+  module('Realm-specific Endpoints | _permissions', function () {
     let testRealm: Realm;
     let request: SuperTest<Test>;
-    let dir: DirResult;
     let dbAdapter: PgAdapter;
 
     function onRealmSetup(args: {
       testRealm: Realm;
       request: SuperTest<Test>;
       dbAdapter: PgAdapter;
-      dir: DirResult;
     }) {
       testRealm = args.testRealm;
       request = args.request;
       dbAdapter = args.dbAdapter;
-      dir = args.dir;
     }
 
-    hooks.beforeEach(async function () {
-      dir = dirSync();
-      copySync(join(__dirname, '..', 'cards'), dir.name);
-    });
-
     module('permissions requests', function (hooks) {
       setupPermissionedRealmCached(hooks, {
-        fileSystem: {},
+        fixture: 'blank',
         permissions: {
           mary: ['read', 'write', 'realm-owner'],
           bob: ['read', 'write'],
diff --git a/packages/realm-server/tests/realm-endpoints/search-test.ts b/packages/realm-server/tests/realm-endpoints/search-test.ts
index 88951a82ae5..c5ec4822dd1 100644
--- a/packages/realm-server/tests/realm-endpoints/search-test.ts
+++ b/packages/realm-server/tests/realm-endpoints/search-test.ts
@@ -58,7 +58,13 @@ module(`realm-endpoints/${basename(__filename)}`, function () {
       let query = () => buildPersonQuery('Mango');
 
       module('public readable realm', function (hooks) {
+        // Uses `realistic` because tests in this module depend on
+        // multiple Person instances (pagination), FileDef instances
+        // beyond person.gts (file-meta queries), and the kitchen-sink
+        // content variety (sparse-fieldsets backward-compat). Sibling
+        // modules below only ever query for Mango and stay on `simple`.
         setupPermissionedRealmCached(hooks, {
+          fixture: 'realistic',
           permissions: {
             '*': ['read'],
           },
@@ -753,6 +759,7 @@ module(`realm-endpoints/${basename(__filename)}`, function () {
 
       module('public readable realm', function (hooks) {
         setupPermissionedRealmCached(hooks, {
+          fixture: 'simple',
           permissions: {
             '*': ['read'],
           },
@@ -829,6 +836,7 @@ module(`realm-endpoints/${basename(__filename)}`, function () {
 
       module('permissioned realm', function (hooks) {
         setupPermissionedRealmCached(hooks, {
+          fixture: 'simple',
           permissions: {
             john: ['read'],
             '@node-test_realm:localhost': ['read', 'realm-owner'],
@@ -886,6 +894,7 @@ module(`realm-endpoints/${basename(__filename)}`, function () {
 
       module('search query validation', function (hooks) {
         setupPermissionedRealmCached(hooks, {
+          fixture: 'simple',
           permissions: {
             '*': ['read'],
             '@node-test_realm:localhost': ['read', 'realm-owner'],
diff --git a/packages/realm-server/tests/realm-endpoints/user-test.ts b/packages/realm-server/tests/realm-endpoints/user-test.ts
index 437659f98fd..8a22fa869ec 100644
--- a/packages/realm-server/tests/realm-endpoints/user-test.ts
+++ b/packages/realm-server/tests/realm-endpoints/user-test.ts
@@ -1,9 +1,7 @@
 import { module, test } from 'qunit';
 import type { Test, SuperTest } from 'supertest';
-import { join, basename } from 'path';
+import { basename } from 'path';
 import type { Server } from 'http';
-import { dirSync, type DirResult } from 'tmp';
-import { copySync } from 'fs-extra';
 import type { Realm } from '@cardstack/runtime-common';
 import {
   setupPermissionedRealmCached,
@@ -28,7 +26,6 @@ module(`realm-endpoints/${basename(__filename)}`, function () {
     let testRealm: Realm;
     let testRealmHttpServer: Server;
     let request: SuperTest<Test>;
-    let dir: DirResult;
     let dbAdapter: PgAdapter;
     let originalLowCreditThreshold: string | undefined;
 
@@ -37,20 +34,16 @@ module(`realm-endpoints/${basename(__filename)}`, function () {
       testRealmHttpServer: Server;
       request: SuperTest<Test>;
       dbAdapter: PgAdapter;
-      dir: DirResult;
     }) {
       testRealm = args.testRealm;
       testRealmHttpServer = args.testRealmHttpServer;
       request = args.request;
       dbAdapter = args.dbAdapter;
-      dir = args.dir;
     }
 
     hooks.beforeEach(async function () {
       originalLowCreditThreshold = process.env.LOW_CREDIT_THRESHOLD;
       process.env.LOW_CREDIT_THRESHOLD = '2000';
-      dir = dirSync();
-      copySync(join(__dirname, '..', 'cards'), dir.name);
     });
 
     hooks.afterEach(async function () {
@@ -64,6 +57,7 @@ module(`realm-endpoints/${basename(__filename)}`, function () {
     });
 
     setupPermissionedRealmCached(hooks, {
+      fixture: 'blank',
       permissions: {
         john: ['read', 'write'],
         '@node-test_realm:localhost': ['read', 'realm-owner'],
@@ -450,7 +444,6 @@ module(`realm-endpoints/${basename(__filename)}`, function () {
     let testRealm: Realm;
     let testRealmHttpServer: Server;
     let request: SuperTest<Test>;
-    let dir: DirResult;
     let dbAdapter: PgAdapter;
     let originalLowCreditThreshold: string | undefined;
 
@@ -459,20 +452,16 @@ module(`realm-endpoints/${basename(__filename)}`, function () {
       testRealmHttpServer: Server;
       request: SuperTest<Test>;
       dbAdapter: PgAdapter;
-      dir: DirResult;
     }) {
       testRealm = args.testRealm;
       testRealmHttpServer = args.testRealmHttpServer;
       request = args.request;
       dbAdapter = args.dbAdapter;
-      dir = args.dir;
     }
 
     hooks.beforeEach(async function () {
       originalLowCreditThreshold = process.env.LOW_CREDIT_THRESHOLD;
       process.env.LOW_CREDIT_THRESHOLD = '2000';
-      dir = dirSync();
-      copySync(join(__dirname, '..', 'cards'), dir.name);
     });
 
     hooks.afterEach(async function () {
@@ -486,6 +475,7 @@ module(`realm-endpoints/${basename(__filename)}`, function () {
     });
 
     setupPermissionedRealmCached(hooks, {
+      fixture: 'blank',
       permissions: {
         john: ['read', 'write'],
         '@node-test_realm:localhost': ['read', 'realm-owner'],