feat: add createGroup function

Signed-off-by: Philip Molares <philip.molares@udo.edu>

src/groups/groups.service.spec.ts

@@ -9,7 +9,7 @@ import { getRepositoryToken } from '@nestjs/typeorm';
 import { Repository } from 'typeorm';
 
 import appConfigMock from '../config/mock/app.config.mock';
-import { NotInDBError } from '../errors/errors';
+import { AlreadyInDBError, NotInDBError } from '../errors/errors';
 import { LoggerModule } from '../logger/logger.module';
 import { Group } from './group.entity';
 import { GroupsService } from './groups.service';
@@ -46,6 +46,33 @@ describe('GroupsService', () => {
     expect(service).toBeDefined();
   });
 
+  describe('createGroup', () => {
+    const groupName = 'testGroup';
+    const displayname = 'Group Test';
+    beforeEach(() => {
+      jest
+        .spyOn(groupRepo, 'save')
+        .mockImplementationOnce(async (group: Group): Promise<Group> => group);
+    });
+    it('successfully creates a group', async () => {
+      const user = await service.createGroup(groupName, displayname);
+      expect(user.name).toEqual(groupName);
+      expect(user.displayName).toEqual(displayname);
+    });
+    it('fails if group name is already taken', async () => {
+      // add additional mock implementation for failure
+      jest.spyOn(groupRepo, 'save').mockImplementationOnce(() => {
+        throw new Error();
+      });
+      // create first group with group name
+      await service.createGroup(groupName, displayname);
+      // attempt to create second group with group name
+      await expect(service.createGroup(groupName, displayname)).rejects.toThrow(
+        AlreadyInDBError,
+      );
+    });
+  });
+
   describe('getGroupByName', () => {
     it('works', async () => {
       jest.spyOn(groupRepo, 'findOne').mockResolvedValueOnce(group);

src/groups/groups.service.ts

@@ -7,7 +7,7 @@ import { Injectable } from '@nestjs/common';
 import { InjectRepository } from '@nestjs/typeorm';
 import { Repository } from 'typeorm';
 
-import { NotInDBError } from '../errors/errors';
+import { AlreadyInDBError, NotInDBError } from '../errors/errors';
 import { ConsoleLoggerService } from '../logger/console-logger.service';
 import { GroupInfoDto } from './group-info.dto';
 import { Group } from './group.entity';
@@ -21,6 +21,35 @@ export class GroupsService {
     this.logger.setContext(GroupsService.name);
   }
 
+  /**
+   * @async
+   * Create a new group with a given name and displayName
+   * @param name - the group name the new group shall have
+   * @param displayName - the display name the new group shall have
+   * @param special - if the group is special or not
+   * @return {Group} the group
+   * @throws {AlreadyInDBError} the group name is already taken.
+   */
+  async createGroup(
+    name: string,
+    displayName: string,
+    special = false,
+  ): Promise<Group> {
+    const group = Group.create(name, displayName);
+    group.special = special;
+    try {
+      return await this.groupRepository.save(group);
+    } catch {
+      this.logger.debug(
+        `A group with the name '${name}' already exists.`,
+        'createGroup',
+      );
+      throw new AlreadyInDBError(
+        `A group with the name '${name}' already exists.`,
+      );
+    }
+  }
+
   /**
    * @async
    * Get a group by their name.