solution

.github/workflows/test.yml-template

@@ -0,0 +1,23 @@
+name: Test
+
+on:
+  pull_request:
+    branches: [ master ]
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+
+    strategy:
+      matrix:
+        node-version: [20.x]
+
+    steps:
+    - uses: actions/checkout@v2
+    - name: Use Node.js ${{ matrix.node-version }}
+      uses: actions/setup-node@v1
+      with:
+        node-version: ${{ matrix.node-version }}
+    - run: npm install
+    - run: npm test

src/fillTank.test.js

@@ -1,11 +1,158 @@
 'use strict';
 
 describe('fillTank', () => {
-  // const { fillTank } = require('./fillTank');
+  const { fillTank } = require('./fillTank');
 
-  it('should ', () => {
+  it(`should be declared`, () => {
+    expect(fillTank).toBeDefined();
+  });
+
+  it(`should return 'undefined'`, () => {
+    const customer = {
+      money: 3000,
+      vehicle: {
+        maxTankCapacity: 40,
+        fuelRemains: 8,
+      },
+    };
+
+    expect(fillTank(customer)).toBeUndefined();
+  });
+
+  it(`should ordered full tank if amount is not given`, () => {
+    const customer = {
+      money: 3000,
+      vehicle: {
+        maxTankCapacity: 40,
+        fuelRemains: 10,
+      },
+    };
+
+    const fuelPrice = 5;
+
+    fillTank(customer, fuelPrice);
+
+    expect(customer).toEqual({
+      money: 2850,
+      vehicle: {
+        maxTankCapacity: 40,
+        fuelRemains: 40,
+      },
+    });
+  });
+
+  it(`should not pour more than tank can accommodate`, () => {
+    const customer = {
+      money: 3000,
+      vehicle: {
+        maxTankCapacity: 40,
+        fuelRemains: 10,
+      },
+    };
+
+    const fuelPrice = 5;
+    const fuelAmount = 50;
+
+    fillTank(customer, fuelPrice, fuelAmount);
 
+    expect(customer).toEqual({
+      money: 2850,
+      vehicle: {
+        maxTankCapacity: 40,
+        fuelRemains: 40,
+      },
+    });
   });
 
-  // write tests here
+  it(`should not fill more than client can pay`, () => {
+    const customer = {
+      money: 50,
+      vehicle: {
+        maxTankCapacity: 40,
+        fuelRemains: 10,
+      },
+    };
+
+    const fuelPrice = 5;
+    const fuelAmount = 20;
+
+    fillTank(customer, fuelPrice, fuelAmount);
+
+    expect(customer).toEqual({
+      money: 0,
+      vehicle: {
+        maxTankCapacity: 40,
+        fuelRemains: 20,
+      },
+    });
+  });
+
+  it(`should not pour at all if poured amount is less than 2 liters`, () => {
+    const customer = {
+      money: 3000,
+      vehicle: {
+        maxTankCapacity: 40,
+        fuelRemains: 8,
+      },
+    };
+
+    const fuelPrice = 5;
+    const fuelAmount = 1;
+
+    fillTank(customer, fuelPrice, fuelAmount);
+
+    expect(customer).toEqual({
+      money: 3000,
+      vehicle: {
+        maxTankCapacity: 40,
+        fuelRemains: 8,
+      },
+    });
+  });
+
+  it(`should correctly round poured amount, and price`, () => {
+    const customer = {
+      money: 3000,
+      vehicle: {
+        maxTankCapacity: 40,
+        fuelRemains: 8,
+      },
+    };
+
+    const fuelPrice = 5.12;
+    const fuelAmount = 4.6;
+
+    fillTank(customer, fuelPrice, fuelAmount);
+
+    expect(customer).toEqual({
+      money: 2976.45,
+      vehicle: {
+        maxTankCapacity: 40,
+        fuelRemains: 12.6,
+      },
+    });
+  });
+
+  it(`should done nothing with negative values for price or amount`, () => {
+    const customer = {
+      money: 3000,
+      vehicle: {
+        maxTankCapacity: 40,
+        fuelRemains: 8,
+      },
+    };
+
+    const fuelPrice = -5;
+    const fuelAmount = -4;
+
+    fillTank(customer, fuelPrice, fuelAmount);
+
+    expect(customer).toEqual({
+      money: 3000,
+      vehicle: {
+        maxTankCapacity: 40,
+        fuelRemains: 8,
+      },
+    });
+  });
 });