add mock CPU classes for abstract class

classes/interfaces/MockCpuInterface.js

@@ -22,14 +22,11 @@ class MockCpuInterface extends CpuInterface {
   }
 
   mapKey() {
-    if (this.resolveKey) {
-      this.resolveKey(5)
-      this.resolveKey = null
-    }
+    this.resolveKey(5)
   }
 
   clearDisplay() {
-    console.log('Screen is cleared')
+    return 'Screen is cleared'
   }
 
   renderDisplay() {
@@ -77,4 +74,5 @@ class MockCpuInterface extends CpuInterface {
 
 module.exports = {
   MockCpuInterface,
+  CpuInterface,
 }

package.json

@@ -35,7 +35,7 @@
       "data/*.js",
       "classes/*.js",
       "classes/interfaces/*.js",
-      "classes/*.js",
+      "!data/keyMap.js",
       "!/node_modules/",
       "!classes/interfaces/DOMCpuInterface.js",
       "!classes/interfaces/TerminalCpuInterface.js"

tests/cpu.test.js

@@ -1,9 +1,9 @@
-describe('CPU tests', async () => {
-  const { CPU } = require('../classes/CPU')
-  const { MockCpuInterface } = require('../classes/interfaces/MockCpuInterface')
-  const cpuInterface = new MockCpuInterface()
-  const cpu = new CPU(cpuInterface)
+const { CPU } = require('../classes/CPU')
+const { MockCpuInterface, CpuInterface } = require('../classes/interfaces/MockCpuInterface')
+const cpuInterface = new MockCpuInterface()
+const cpu = new CPU(cpuInterface)
 
+describe('CPU tests', async () => {
   test('CPU should not execute after halting', async () => {
     cpu.load({ data: 0x0000 })
     cpu.halted = true
@@ -41,6 +41,22 @@ describe('CPU tests', async () => {
     )
   })
 
+  test('Tick should disable sound if sound is enabled and sound timer is zero', async () => {
+    cpu.load({ data: [0x00e0] })
+    await cpu.step()
+    cpu.soundEnabled = true
+    await cpu.tick()
+
+    expect(cpu.soundEnabled).toBe(false)
+  })
+
+  test('3: CLS (00e0) - Program should clear the display', async () => {
+    cpu.load({ data: [0x00e0] })
+    const mockClearDisplay = cpu.interface.clearDisplay()
+
+    expect(mockClearDisplay).toBe('Screen is cleared')
+  })
+
   test('3: RET (00ee) - Program counter should be set to stack pointer, then decrement stack pointer', async () => {
     cpu.load({ data: [0x00ee] })
     cpu.SP = 0x2
@@ -426,12 +442,30 @@ describe('CPU tests', async () => {
   })
 
   test('28: LD_VX_N (Fx0A) - Register x should be set to the value of keypress', async () => {
-    cpu.load({ data: [0xfb0a] })
+    cpu.load({ data: [0xfb0a, 0xfa07] })
     await cpu.step()
 
     expect(cpu.registers[0xb]).toBe(5)
   })
 
+  test('28: LD_VX_N (Fx0A) - Error should be thrown if CPU is halted during waitKey', async () => {
+    cpu.load({ data: [0xfb0a] })
+    let error
+    try {
+      if (!cpu.halted) {
+        cpu.halt()
+        await cpu.step()
+      }
+    } catch (e) {
+      error = e
+    }
+    expect(error).toEqual(
+      new Error(
+        'A problem has been detected and Chip-8 has been shut down to prevent damage to your computer.'
+      )
+    )
+  })
+
   test('29: LD_DT_VX (Fx15) - Delay timer should be set to the value of register x', async () => {
     // todo tick
     cpu.load({ data: [0xfb15] })
@@ -584,3 +618,106 @@ describe('CPU tests', async () => {
     expect(error).toEqual(new Error('Illegal instruction.'))
   })
 })
+
+describe('CPU abstract class', () => {
+  class ChildCpuInterface extends CpuInterface {
+    constructor() {
+      super()
+    }
+  }
+
+  test('CPU interface should throw an error if it is instantiated directly', () => {
+    let error
+    try {
+      new CpuInterface()
+    } catch (e) {
+      error = e
+    }
+    // BSOD on halted program
+    expect(error).toEqual(new Error('Cannot instantiate abstract class'))
+  })
+
+  test('CPU interface must have clearDisplay method', () => {
+    let error
+    try {
+      const childCpuInterface = new ChildCpuInterface()
+      childCpuInterface.clearDisplay()
+    } catch (e) {
+      error = e
+    }
+    // BSOD on halted program
+    expect(error).toEqual(new Error('Must be implemented on the inherited class.'))
+  })
+
+  test('CPU interface must have renderDisplay method', () => {
+    let error
+    try {
+      const childCpuInterface = new ChildCpuInterface()
+      childCpuInterface.renderDisplay()
+    } catch (e) {
+      error = e
+    }
+    // BSOD on halted program
+    expect(error).toEqual(new Error('Must be implemented on the inherited class.'))
+  })
+
+  test('CPU interface must have waitKey method', () => {
+    let error
+    try {
+      const childCpuInterface = new ChildCpuInterface()
+      childCpuInterface.waitKey()
+    } catch (e) {
+      error = e
+    }
+    // BSOD on halted program
+    expect(error).toEqual(new Error('Must be implemented on the inherited class.'))
+  })
+
+  test('CPU interface must have getKeys method', () => {
+    let error
+    try {
+      const childCpuInterface = new ChildCpuInterface()
+      childCpuInterface.getKeys()
+    } catch (e) {
+      error = e
+    }
+    // BSOD on halted program
+    expect(error).toEqual(new Error('Must be implemented on the inherited class.'))
+  })
+
+  test('CPU interface must have drawPixel method', () => {
+    let error
+    try {
+      const childCpuInterface = new ChildCpuInterface()
+      childCpuInterface.drawPixel()
+    } catch (e) {
+      error = e
+    }
+    // BSOD on halted program
+    expect(error).toEqual(new Error('Must be implemented on the inherited class.'))
+  })
+
+  test('CPU interface must have enableSound method', () => {
+    let error
+    try {
+      const childCpuInterface = new ChildCpuInterface()
+      childCpuInterface.enableSound()
+    } catch (e) {
+      error = e
+    }
+    // BSOD on halted program
+    expect(error).toEqual(new Error('Must be implemented on the inherited class.'))
+  })
+
+  test('CPU interface must have disableSound method', () => {
+    let error
+    try {
+      const childCpuInterface = new ChildCpuInterface()
+      childCpuInterface.disableSound()
+    } catch (e) {
+      error = e
+    }
+    // BSOD on halted program
+    expect(error).toEqual(new Error('Must be implemented on the inherited class.'))
+  })
+})