diff --git a/app/api/meal-plan-generator/services.ts b/app/api/meal-plan-generator/services.ts
index 54f126c..0130db5 100644
--- a/app/api/meal-plan-generator/services.ts
+++ b/app/api/meal-plan-generator/services.ts
@@ -66,7 +66,7 @@ function validateBody(body: PlanGeneratorFormInput) {
 
 async function mealsByMealTypeAndTagIds(mealType: MealType, tagIds: number[]) {
   return await prisma.meal.findMany({
-        where: { 
+        where: {
           tags: { some: { id: { in: tagIds } } },
           suggestedMealType: { has: mealType }
         },
@@ -74,10 +74,10 @@ async function mealsByMealTypeAndTagIds(mealType: MealType, tagIds: number[]) {
       });
 }
 
-async function mealsByTagIds(tagIds: number[]) {
+async function mealsByMealType(mealType: MealType) {
   return await prisma.meal.findMany({
-        where: { 
-          tags: { some: { id: { in: tagIds } } }
+        where: {
+          suggestedMealType: { has: mealType }
         },
         include: { tags: true }
       });
@@ -129,9 +129,9 @@ export async function generateMealPlan(body: PlanGeneratorFormInput, userId: str
           const failedToCreateObject = await buildFailedToCreateObject(tagIds, parsedDate, mealType)
           failedToCreate.push(failedToCreateObject)
 
-          const mealsByTags = await mealsByTagIds(tagIds)
+          const mealsByType = await mealsByMealType(mealType)
 
-          return findBestMeal(mealsByTags, tagIds)
+          return findBestMeal(mealsByType, tagIds)
         }
         else {
           return findBestMeal(mealsWithMealType, tagIds)
@@ -139,12 +139,12 @@ export async function generateMealPlan(body: PlanGeneratorFormInput, userId: str
       })()
 
       if (meal === undefined) {
-        continue 
+        continue
       }
 
       const mealPlan = {
         date: parsedDate,
-        type: mealType, 
+        type: mealType,
         mealId: meal.id,
         userId
       };
diff --git a/app/api/meals/route.ts b/app/api/meals/route.ts
index e0b2dbd..400050b 100644
--- a/app/api/meals/route.ts
+++ b/app/api/meals/route.ts
@@ -33,7 +33,7 @@ export async function POST(request: Request) {
         name: body.name,
         description: body.description || null,
         ingredients: body.ingredients,
-        recipe: body.recipe || null,
+        recipe: body.recipe || [],
         suggestedMealType: body.suggestedMealType,
         userId: session.user.id,
         tags: {
diff --git a/eslint.config.mjs b/eslint.config.mjs
index 05e726d..b971c59 100644
--- a/eslint.config.mjs
+++ b/eslint.config.mjs
@@ -13,6 +13,12 @@ const eslintConfig = defineConfig([
     "build/**",
     "next-env.d.ts",
   ]),
+  {
+    files: ["test/**/*.ts", "test/**/*.tsx"],
+    rules: {
+      "@typescript-eslint/no-explicit-any": "off",
+    },
+  },
 ]);
 
 export default eslintConfig;
diff --git a/package-lock.json b/package-lock.json
index 431d208..d9761b9 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -36,6 +36,7 @@
         "dotenv-cli": "^11.0.0",
         "eslint": "^9",
         "eslint-config-next": "16.0.1",
+        "fishery": "^2.4.0",
         "jsdom": "^26.0.0",
         "prisma": "^6.19.0",
         "tsx": "^4.20.6",
@@ -5367,6 +5368,16 @@
         "url": "https://github.com/sponsors/sindresorhus"
       }
     },
+    "node_modules/fishery": {
+      "version": "2.4.0",
+      "resolved": "https://registry.npmjs.org/fishery/-/fishery-2.4.0.tgz",
+      "integrity": "sha512-QgeTlvgNhVGuMztrfAhlSIBs3rD3l9RMjl9I15yb/lnrx3njrOhvegr2L3LWdqvXwYfQjdQGpglyAfHH2J8DRA==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "lodash.mergewith": "^4.6.2"
+      }
+    },
     "node_modules/flat-cache": {
       "version": "4.0.1",
       "resolved": "https://registry.npmjs.org/flat-cache/-/flat-cache-4.0.1.tgz",
@@ -6784,6 +6795,13 @@
       "dev": true,
       "license": "MIT"
     },
+    "node_modules/lodash.mergewith": {
+      "version": "4.6.2",
+      "resolved": "https://registry.npmjs.org/lodash.mergewith/-/lodash.mergewith-4.6.2.tgz",
+      "integrity": "sha512-GK3g5RPZWTRSeLSpgP8Xhra+pnjBC56q9FZYe1d5RN3TJ35dbkGy3YqBSMbyCrlbi+CM9Z3Jk5yTL7RCsqboyQ==",
+      "dev": true,
+      "license": "MIT"
+    },
     "node_modules/loose-envify": {
       "version": "1.4.0",
       "resolved": "https://registry.npmjs.org/loose-envify/-/loose-envify-1.4.0.tgz",
diff --git a/package.json b/package.json
index 99131f8..df47aee 100644
--- a/package.json
+++ b/package.json
@@ -40,6 +40,7 @@
     "dotenv-cli": "^11.0.0",
     "eslint": "^9",
     "eslint-config-next": "16.0.1",
+    "fishery": "^2.4.0",
     "jsdom": "^26.0.0",
     "prisma": "^6.19.0",
     "tsx": "^4.20.6",
diff --git a/prisma/schema.prisma b/prisma/schema.prisma
index 290f27c..7f38bc6 100644
--- a/prisma/schema.prisma
+++ b/prisma/schema.prisma
@@ -17,7 +17,7 @@ model Meal {
   mealPlans         MealPlan[]
   suggestedMealType MealType[]
   tags              Tag[]      @relation("MealTags")
-  userId            String?    
+  userId            String?
   user              User?      @relation(fields: [userId], references: [id])
 }
 
@@ -52,7 +52,7 @@ model User {
   createdAt   DateTime         @default(now())
   mealPlans   MealPlan[] //one to many
   preferences UserPreference[]
-  meals       Meal[]           // user-created meals
+  meals       Meal[] // user-created meals
 }
 
 enum MealType {
diff --git a/test/api/meal-plan-generator/services/find_best_meal.test.ts b/test/api/meal-plan-generator/services/find_best_meal.test.ts
new file mode 100644
index 0000000..3ddf910
--- /dev/null
+++ b/test/api/meal-plan-generator/services/find_best_meal.test.ts
@@ -0,0 +1,34 @@
+import { describe, it, expect } from "vitest"
+import { findBestMeal } from "@/app/api/meal-plan-generator/services"
+import tagFactory from "@/test/factories/tag_factory"
+import mealFactory from "@/test/factories/meal_factory"
+
+describe("findBestMeal", () => {
+  it('finds the meal with the most matched tags', async () => {
+    const vegetarianTag = await tagFactory.vegetarian().create()
+    const noGlutenTag = await tagFactory.noGluten().create()
+    const fruitsTag = await tagFactory.fruits().create()
+    const meatTag = await tagFactory.meat().create()
+    const veganTag = await tagFactory.vegan().create()
+    const quickTag = await tagFactory.quick().create()
+
+    const meal1 = await mealFactory.create({
+      name: "Owsianka z Owocami",
+      tags: [vegetarianTag, fruitsTag, quickTag, noGlutenTag]
+    })
+    const meal2 = await mealFactory.create({
+      name: "Kotlet schabowy",
+      tags: [meatTag]
+    })
+    const meal3 = await mealFactory.create({
+      name: "Makaron bez niczego",
+      tags: [veganTag]
+    })
+
+    const meals = [meal1, meal2, meal3]
+    const searchedTags = [vegetarianTag.id, quickTag.id, veganTag.id]
+    const bestMeal = findBestMeal(meals, searchedTags)
+
+    expect(bestMeal.name).toBe("Owsianka z Owocami")
+  })
+})
diff --git a/test/api/meal-plan-generator/services/generate_meal_plan.test.ts b/test/api/meal-plan-generator/services/generate_meal_plan.test.ts
new file mode 100644
index 0000000..369f643
--- /dev/null
+++ b/test/api/meal-plan-generator/services/generate_meal_plan.test.ts
@@ -0,0 +1,78 @@
+import { describe, it, expect, beforeEach } from "vitest"
+import prisma from "@/lib/prisma"
+import { generateMealPlan } from "@/app/api/meal-plan-generator/services"
+import tagFactory from "@/test/factories/tag_factory"
+import mealFactory, { MealWithTags } from "@/test/factories/meal_factory"
+import { MealType } from "@/app/generated/prisma/enums"
+import userFactory from "@/test/factories/user_factory"
+import { type Tag, type User, type MealPlan } from "@/app/generated/prisma/client"
+
+describe("generateMealPlan", () => {
+  let user: User
+  let noGlutenTag: Tag
+  let fruitsTag: Tag
+  let meatTag: Tag
+  let quickTag: Tag
+  let dessert: MealWithTags
+  let lunch: MealWithTags
+
+  beforeEach(async() => {
+    user = await userFactory.create()
+    noGlutenTag = await tagFactory.noGluten().create()
+    fruitsTag = await tagFactory.fruits().create()
+    meatTag = await tagFactory.meat().create()
+    quickTag = await tagFactory.quick().create()
+    dessert = await mealFactory.create({
+      name: "Deser owocowy",
+      suggestedMealType: [MealType.DESSERT],
+      tags: [noGlutenTag, fruitsTag]
+    })
+    lunch = await mealFactory.create({
+      name: "Schabowy",
+      suggestedMealType: [MealType.LUNCH],
+      tags: [meatTag, quickTag]
+    })
+  })
+
+  it("Generates meal plan with meal with provided meal type and tags", async () => {
+    const requestBody = {
+      "2025-12-06": {
+        "BREAKFAST": [],
+        "LUNCH": [meatTag, quickTag].map((tag) => tag.id),
+        "DESSERT": [],
+        "DINNER": []
+      },
+    }
+
+    const { count, failedToCreate } = await generateMealPlan(requestBody, user.id)
+
+    expect(count).toEqual(1)
+    expect(failedToCreate.length).toEqual(0)
+
+    const mealPlan = await prisma.mealPlan.findFirst() as MealPlan
+    expect(mealPlan.type).toEqual(MealType.LUNCH)
+    expect(mealPlan.mealId).toEqual(lunch.id)
+    expect(mealPlan.date).toEqual(new Date("2025-12-06"))
+  })
+
+  it("Generates meal plan with random meal with provided meal type if no meal with type and tags is found", async () => {
+    const requestBody = {
+      "2025-12-06": {
+        "BREAKFAST": [],
+        "LUNCH": [],
+        "DESSERT": [meatTag, quickTag].map((tag) => tag.id),
+        "DINNER": []
+      },
+    }
+
+    const { count, failedToCreate } = await generateMealPlan(requestBody, user.id)
+
+    expect(count).toEqual(1)
+    expect(failedToCreate.length).toEqual(1)
+
+    const mealPlan = await prisma.mealPlan.findFirst() as MealPlan
+    expect(mealPlan.type).toEqual(MealType.DESSERT)
+    expect(mealPlan.mealId).toEqual(dessert.id)
+    expect(mealPlan.date).toEqual(new Date("2025-12-06"))
+  })
+})
diff --git a/test/api/meals.test.ts b/test/api/meals.test.ts
index 810689d..6799a75 100644
--- a/test/api/meals.test.ts
+++ b/test/api/meals.test.ts
@@ -1,6 +1,7 @@
 import { describe, it, expect, vi, beforeEach } from "vitest";
 import prisma from "@/lib/prisma";
-import { createTag } from "../helpers/records_creator";
+import tagFactory from "@/test/factories/tag_factory"
+import userFactory from "@/test/factories/user_factory"
 
 vi.mock("@/lib/auth", () => ({
   getSession: vi.fn(),
@@ -15,22 +16,12 @@ describe("POST /api/meals", () => {
   });
 
   it("creates a meal owned by the current user and connects tags", async () => {
-    const userId = "user_1";
-
-    await prisma.user.create({
-      data: {
-        id: userId,
-        email: "user_1@example.com",
-        password: "hashed-password",
-        name: "User 1",
-      },
-    });
-
-    const tag1 = await createTag("Wegetariańskie");
-    const tag2 = await createTag("Szybkie");
+    const user = await userFactory.create()
+    const tag1 = await tagFactory.vegetarian().create()
+    const tag2 = await tagFactory.quick().create()
 
     vi.mocked(getSession).mockResolvedValue({
-      user: { id: userId },
+      user: { id: user.id },
     } as any);
 
     const { POST } = await import("@/app/api/meals/route");
@@ -54,13 +45,13 @@ describe("POST /api/meals", () => {
     const payload = await res.json();
     expect(payload.ok).toBe(true);
     expect(payload.meal.name).toBe("Owsianka");
-    expect(payload.meal.userId).toBe(userId);
+    expect(payload.meal.userId).toBe(user.id);
     expect(payload.meal.tags.map((t: any) => t.id).sort()).toEqual(
       [tag1.id, tag2.id].sort()
     );
 
     const created = await prisma.meal.findFirst({
-      where: { name: "Owsianka", userId },
+      where: { name: "Owsianka", userId: user.id },
       include: { tags: true },
     });
 
diff --git a/test/api/services.test.ts b/test/api/services.test.ts
deleted file mode 100644
index ad4afb1..0000000
--- a/test/api/services.test.ts
+++ /dev/null
@@ -1,52 +0,0 @@
-import { describe, it, expect } from "vitest"
-import prisma from "@/lib/prisma"
-import { createTag, toIdsArray } from "../helpers/records_creator"
-import { findBestMeal } from "@/app/api/meal-plan-generator/services"
-
-describe("findBestMeal", () => {
-  it('finds the meal with the most matched tags', async () => {
-    const vegetarianTag = await createTag("Wegetariańskie")
-    const noGlutenTag = await createTag("Bezglutenowe")
-    const fruitsTag = await createTag("Owoce")
-    const meatTag = await createTag("Mięso")
-    const veganTag = await createTag("Wegańskie")
-    const fastTag = await createTag("Szybkie")
-
-    const meal1 = await prisma.meal.create({
-      data: { 
-        name: "Owsianka z Owocami", 
-        ingredients: {}, 
-        tags: { 
-          connect: toIdsArray([vegetarianTag, fruitsTag, fastTag, noGlutenTag])
-        }
-       },
-       include: { tags: true }
-    })
-    const meal2 = await prisma.meal.create({
-      data: { 
-        name: "Kotlet schabowy", 
-        ingredients: {}, 
-        tags: { 
-          connect: toIdsArray([meatTag])
-        }
-       },
-       include: { tags: true }
-    })
-    const meal3 = await prisma.meal.create({
-      data: { 
-        name: "Makaron bez niczego", 
-        ingredients: {}, 
-        tags: { 
-          connect: toIdsArray([veganTag])
-        }
-       },
-       include: { tags: true }
-    })
-
-    const meals = [meal1, meal2, meal3]
-    const searchedTags = [vegetarianTag.id, fastTag.id, veganTag.id]
-    const bestMeal = findBestMeal(meals, searchedTags)
-
-    expect(bestMeal.name).toBe("Owsianka z Owocami")
-  })
-})
diff --git a/test/factories/meal_factory.ts b/test/factories/meal_factory.ts
new file mode 100644
index 0000000..b79ab9b
--- /dev/null
+++ b/test/factories/meal_factory.ts
@@ -0,0 +1,42 @@
+import prisma from "@/lib/prisma"
+import { Factory } from "fishery"
+import { Prisma, type Meal, type Tag} from "@/app/generated/prisma/client"
+import { JsonValue } from "@prisma/client/runtime/library"
+
+export interface MealWithTags extends Meal {
+  tags: Tag[];
+}
+
+class MealFactory extends Factory<MealWithTags> { }
+
+const mealFactory = MealFactory.define(({ sequence, params, onCreate }) => {
+  onCreate((meal) => {
+    const tags = meal.tags || []
+
+    return prisma.meal.create({
+      data: {
+        ...meal,
+        id: undefined,
+        ingredients: (meal.ingredients ?? {}) as Prisma.InputJsonValue,
+        recipe: (meal.recipe ?? Prisma.JsonNull) as Prisma.InputJsonValue,
+        tags: {
+          connect: tags.map(tag => ({ id: tag.id }))
+        }
+      },
+      include: { tags: true }
+    })
+  })
+
+  return {
+    id: sequence,
+    name: params.name!,
+    ingredients: (params.ingredients || {}) as JsonValue,
+    description: params.description ?? null,
+    recipe: (params.recipe || []) as JsonValue,
+    suggestedMealType: params.suggestedMealType || [],
+    userId: params.userId ?? null,
+    tags: params.tags || []
+  }
+})
+
+export default mealFactory
diff --git a/test/factories/tag_factory.ts b/test/factories/tag_factory.ts
new file mode 100644
index 0000000..bde4149
--- /dev/null
+++ b/test/factories/tag_factory.ts
@@ -0,0 +1,33 @@
+import prisma from "@/lib/prisma"
+import { Factory } from "fishery"
+import { Tag, TagSection } from "@/app/generated/prisma/client"
+
+class TagFactory extends Factory<Tag> {
+  vegetarian() { return this.params({ name: "Wegetariańskie" }) }
+  noGluten()   { return this.params({ name: "Bezglutenowe" }) }
+  fruits()     { return this.params({ name: "Owoce" }) }
+  meat()       { return this.params({ name: "Mięso" }) }
+  vegan()      { return this.params({ name: "Wegańskie" }) }
+  quick()      { return this.params({ name: "Szybkie" }) }
+}
+
+const tagFactory = TagFactory.define(({ sequence, params, onCreate }) => {
+  onCreate((tag) => {
+    return prisma.tag.create(
+      {
+        data: {
+          ...tag,
+          id: undefined
+        }
+      }
+    )
+  })
+
+  return {
+    id: sequence,
+    name: params.name!,
+    section: params.section || TagSection.UNIVERSAL,
+  }
+})
+
+export default tagFactory
diff --git a/test/factories/user_factory.ts b/test/factories/user_factory.ts
new file mode 100644
index 0000000..0e1856f
--- /dev/null
+++ b/test/factories/user_factory.ts
@@ -0,0 +1,21 @@
+import prisma from "@/lib/prisma"
+import { Factory } from "fishery"
+import { User } from "@/app/generated/prisma/client"
+
+class UserFactory extends Factory<User> {}
+
+const userFactory = UserFactory.define(({ sequence, params, onCreate }) => {
+  onCreate((user) => {
+    return prisma.user.create({ data: user });
+  })
+
+  return {
+    id: `user_${sequence}`,
+    name: params.name || `User ${sequence}`,
+    email: params.email || `user_${sequence}@example.com`,
+    password: params.password || "hashed-password",
+    createdAt: new Date()
+  }
+})
+
+export default userFactory
diff --git a/test/helpers/reset-db.ts b/test/helpers/reset-db.ts
index 8093fe4..68d5ee5 100644
--- a/test/helpers/reset-db.ts
+++ b/test/helpers/reset-db.ts
@@ -1,5 +1,3 @@
-// src/tests/helpers/reset-db.ts
-
 import prisma from "@/lib/prisma"
 
 export default async function resetDB() {
diff --git a/tsconfig.json b/tsconfig.json
index 3a13f90..88497ba 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -19,7 +19,8 @@
       }
     ],
     "paths": {
-      "@/*": ["./*"]
+      "@/*": ["./*"],
+      "@test/*": ["./test/*"]
     }
   },
   "include": [
diff --git a/vitest.config.mts b/vitest.config.mts
index 6903606..1c161ab 100644
--- a/vitest.config.mts
+++ b/vitest.config.mts
@@ -1,10 +1,11 @@
 import { defineConfig } from 'vitest/config'
 import react from '@vitejs/plugin-react'
 import tsconfigPaths from 'vite-tsconfig-paths'
- 
+
 export default defineConfig({
   plugins: [tsconfigPaths(), react()],
   test: {
+    maxWorkers: 1,
     environment: 'jsdom',
     setupFiles: ['test/helpers/setup.ts']
   },