diff --git a/mods/mods_available/kdmod/ShareTestService.js b/mods/mods_available/kdmod/ShareTestService.js
new file mode 100644
index 00000000..7686b634
--- /dev/null
+++ b/mods/mods_available/kdmod/ShareTestService.js
@@ -0,0 +1,129 @@
+// TODO: accessing these imports directly from a mod is not really
+//       the way mods are intended to work; this is temporary until
+//       we have these things registered in "useapi".
+const {
+    get_user,
+    generate_system_fsentries,
+    invalidate_cached_user,
+} = require('../../../packages/backend/src/helpers');
+// const { HLWrite } = require('../../../packages/backend/src/filesystem/hl_operations/hl_write');
+const { Actor, UserActorType }
+    = require('../../../packages/backend/src/services/auth/Actor');
+const { DB_WRITE } = require('../../../packages/backend/src/services/database/consts');
+
+    
+class ShareTestService extends use.Service {
+    static MODULES = {
+        uuidv4: require('uuid').v4,
+    }
+
+    async _init () {
+        const svc_commands = this.services.get('commands');
+        this._register_commands(svc_commands);
+        
+        this.scenarios = require('./data/sharetest_scenarios');
+
+        const svc_db = this.services.get('database');
+        this.db = svc_db.get(svc_db.DB_WRITE, 'share-test');
+    }
+    
+    _register_commands (commands) {
+        commands.registerCommands('share-test', [
+            {
+                id: 'start',
+                description: '',
+                handler: async (_, log) => {
+                    this.runit();
+                }
+            }
+        ]);
+    }
+    
+    async runit () {
+        await this.teardown_();
+        await this.setup_();
+        
+        for ( const scenario of this.scenarios ) {
+            this.run_scenario_(scenario);
+        }
+        
+        await this.teardown_();
+    }
+    
+    async setup_ () {
+        await this.create_test_user_('testuser_eric');
+        await this.create_test_user_('testuser_stan');
+        await this.create_test_user_('testuser_kyle');
+        await this.create_test_user_('testuser_kenny');
+    }
+    async run_scenario_ (scenario) {
+        // Run sequence
+        for ( const step of scenario.sequence ) {
+            const method = this[`__scenario:${step.call}`];
+            const user = await get_user({ username: step.as })
+            const actor = Actor.create(UserActorType, { user });
+            const generated = { user, actor };
+            await method.call(this, generated, scenario.with);
+        }
+    }
+    async teardown_ () {
+        await this.delete_test_user_('testuser_eric');
+        await this.delete_test_user_('testuser_stan');
+        await this.delete_test_user_('testuser_kyle');
+        await this.delete_test_user_('testuser_kenny');
+    }
+
+    async create_test_user_ (username) {
+        await this.db.write(
+            `
+                INSERT INTO user (uuid, username, email, free_storage, password)
+                VALUES (?, ?, ?, ?, ?)
+            `,
+            [
+                this.modules.uuidv4(),
+                username,
+                username + '@example.com',
+                1024 * 1024 * 500, // 500 MiB
+                this.modules.uuidv4(),
+            ],
+        );
+        const user = await get_user({ username });
+        await generate_system_fsentries(user);
+        invalidate_cached_user(user);
+        return user;
+    }
+    
+    async delete_test_user_ (username) {
+        await this.db.write(
+            `
+                DELETE FROM user WHERE username=? LIMIT 1
+            `,
+            [username],
+        );
+    }
+    
+    // API for scenarios
+    async ['__scenario:create-example-file'] (
+        { user },
+        { name, contents },
+    ) {
+        console.log('test -> create-example-file',
+            user, name, contents);
+        // const hl_write = new HLWrite();
+        // await hl_write.run({
+        //     destination_or_parent: '/'+user.username+'/Desktop',
+        //     specified_name: name,
+
+        // });
+    }
+    async ['__scenario:assert-no-access'] (
+        { user },
+        { path },
+    ) {
+        console.log('test -> assert-no-access', user, path);
+    }
+}
+
+module.exports = {
+    ShareTestService,
+};
diff --git a/mods/mods_available/kdmod/data/sharetest_scenarios.js b/mods/mods_available/kdmod/data/sharetest_scenarios.js
new file mode 100644
index 00000000..8065baf7
--- /dev/null
+++ b/mods/mods_available/kdmod/data/sharetest_scenarios.js
@@ -0,0 +1,22 @@
+module.exports = [
+    {
+        title: `Kyle creates a file; Eric tries access read it`,
+        sequence: [
+            {
+                call: 'create-example-file',
+                as: 'testuser_kyle',
+                with: {
+                    name: 'example.txt',
+                    contents: 'secret file',
+                }
+            },
+            {
+                call: 'assert-no-access',
+                as: 'testuser_eric',
+                with: {
+                    path: '/testuser_kyle/Desktop/example.txt'
+                }
+            },
+        ]
+    }
+];
diff --git a/mods/mods_available/kdmod/module.js b/mods/mods_available/kdmod/module.js
index 1079827a..e6487687 100644
--- a/mods/mods_available/kdmod/module.js
+++ b/mods/mods_available/kdmod/module.js
@@ -4,5 +4,8 @@ module.exports = class BillingModule extends use.Module {
 
         const { CustomPuterService } = require('./CustomPuterService.js');
         services.registerService('__custom-puter', CustomPuterService);
+        
+        const { ShareTestService } = require('./ShareTestService.js');
+        services.registerService('__share-test', ShareTestService);
     }
 }