test: Add tests for new util functions

- add tests for rgbDecimalToHex
- add tests for decimalToHex

src/support/__tests__/utils.cy.js

@@ -0,0 +1,21 @@
+import Utils from '../utils'
+
+describe('Utils rgbDecimalToHex', () => {
+  it('should return normal hex colors', (done) => {
+    let res_black = Utils.rgbDecimalToHex(0,0,0)
+    expect(res_black).to.equal('#000000')
+    let res_white = Utils.rgbDecimalToHex(255,255,255)
+    expect(res_white).to.equal('#ffffff')
+    done()
+  })
+})
+
+describe('Utils decimalToHex', () => {
+  it('should convert decimals to 2 digit hex values', (done) => {
+    expect( Utils.decimalToHex(15)).to.equal('0f')
+    expect( Utils.decimalToHex(0)).to.equal('00')
+    expect( Utils.decimalToHex(16)).to.equal('10')
+    expect( Utils.decimalToHex(255)).to.equal('ff')
+    done()
+  })
+})