feat: Added setFontSize method unit tests

src/lib/directives/ng2-fittext.directive.ts

@@ -29,7 +29,7 @@ export class Ng2FittextDirective
 
   @Input('modelToWatch') modelToWatch: any;
 
-  @Output() fontSizeChanged = new EventEmitter();
+  @Output() fontSizeChanged: EventEmitter<any> = new EventEmitter();
 
   private fontSize = 1000;
   private speed = 1.05;
@@ -37,24 +37,27 @@ export class Ng2FittextDirective
 
   constructor(public el: ElementRef, public renderer: Renderer2) {}
 
-  setFontSize(fontSize: number) {
+  setFontSize(fontSize: number): void {
-    if (this.isVisible() && !this.done) {
+    if (this.isVisible() && !this.isDone()) {
       if (fontSize < this.minFontSize) {
         fontSize = this.minFontSize;
       }
       if (fontSize > this.maxFontSize) {
         fontSize = this.maxFontSize;
       }
-
       this.fontSize = fontSize;
       this.fontSizeChanged.emit(fontSize);
-      return this.el.nativeElement.style.setProperty(
+      this.el.nativeElement.style.setProperty(
         'font-size',
         fontSize.toString() + 'px'
       );
     }
   }
 
+  getFontSize(): number {
+    return this.fontSize;
+  }
+
   calculateFontSize(fontSize: number, speed: number) {
     return Math.floor(fontSize / speed);
   }
@@ -95,7 +98,7 @@ export class Ng2FittextDirective
   }
 
   ngAfterViewInit() {
-    if (this.isVisible() && !this.done) {
+    if (this.isVisible() && !this.isDone()) {
       if (this.fittext) {
         const overflow = this.container
           ? this.checkOverflow(this.container, this.el.nativeElement)
@@ -146,7 +149,11 @@ export class Ng2FittextDirective
       : this.el.nativeElement.parentElement.clientWidth;
   }
 
-  private isVisible(): boolean {
+  isDone(): boolean {
+    return this.done;
+  }
+
+  isVisible(): boolean {
     return this.getStartFontSizeFromHeight() > 0;
   }
 }

src/lib/directives/specs/ng2-fittext.directive.spec.ts

@@ -0,0 +1,90 @@
+import { Ng2FittextDirective } from '../ng2-fittext.directive';
+import { Renderer2, ElementRef } from '@angular/core';
+
+describe('Class: Ng2FittextDirective', () => {
+  let ng2FittextDirective: Ng2FittextDirective;
+  let elMock: ElementRef;
+  let rendererMock: Renderer2;
+
+  beforeEach(() => {
+    elMock = {} as ElementRef;
+    rendererMock = {} as Renderer2;
+    ng2FittextDirective = new Ng2FittextDirective(elMock, rendererMock);
+  });
+
+  describe('Method: setFontSize', () => {
+    let newFontSize: number;
+    let isVisibleSpy: jasmine.Spy;
+    let isDoneSpy: jasmine.Spy;
+
+    beforeEach(() => {
+      newFontSize = 100;
+      isVisibleSpy = spyOn(ng2FittextDirective, 'isVisible').and.returnValue(
+        true
+      );
+      isDoneSpy = spyOn(ng2FittextDirective, 'isDone').and.returnValue(false);
+      elMock.nativeElement = {
+        style: {
+          setProperty: () => {},
+        },
+      };
+    });
+
+    it('Should not change the font size if the element is not visible', () => {
+      isVisibleSpy.and.returnValue(false);
+      const previousFontSize: number = ng2FittextDirective.getFontSize();
+      ng2FittextDirective.setFontSize(newFontSize);
+      expect(ng2FittextDirective.getFontSize()).toEqual(previousFontSize);
+    });
+
+    it('Should not change the font size if the fitting operation is done', () => {
+      isDoneSpy.and.returnValue(true);
+      const previousFontSize: number = ng2FittextDirective.getFontSize();
+      ng2FittextDirective.setFontSize(newFontSize);
+      expect(ng2FittextDirective.getFontSize()).toEqual(previousFontSize);
+    });
+
+    it('Should use the minFontSize property value if the specified font size is smaller', () => {
+      const minFontSize: number = ng2FittextDirective.minFontSize;
+      newFontSize = 5;
+      ng2FittextDirective.setFontSize(newFontSize);
+      const currentFontSize: number = ng2FittextDirective.getFontSize();
+      expect(currentFontSize).toEqual(minFontSize);
+    });
+
+    it('Should use the maxFontSize property value if the specified font size is bigger', () => {
+      const maxFontSize: number = ng2FittextDirective.maxFontSize;
+      newFontSize = 1001;
+      ng2FittextDirective.setFontSize(newFontSize);
+      const currentFontSize: number = ng2FittextDirective.getFontSize();
+      expect(currentFontSize).toEqual(maxFontSize);
+    });
+
+    it('Should set a new fontSize value', () => {
+      newFontSize = 500;
+      ng2FittextDirective.setFontSize(newFontSize);
+      const currentFontSize: number = ng2FittextDirective.getFontSize();
+      expect(currentFontSize).toEqual(newFontSize);
+    });
+
+    it('Should emit the font size change', () => {
+      newFontSize = 500;
+      spyOn(ng2FittextDirective.fontSizeChanged, 'emit');
+      ng2FittextDirective.setFontSize(newFontSize);
+      const currentFontSize: number = ng2FittextDirective.getFontSize();
+      expect(ng2FittextDirective.fontSizeChanged.emit).toHaveBeenCalledWith(
+        newFontSize
+      );
+    });
+
+    it('Should update the nativeElement with the new font size', () => {
+      newFontSize = 500;
+      spyOn(ng2FittextDirective.el.nativeElement.style, 'setProperty');
+      ng2FittextDirective.setFontSize(newFontSize);
+      const currentFontSize: number = ng2FittextDirective.getFontSize();
+      expect(
+        ng2FittextDirective.el.nativeElement.style.setProperty
+      ).toHaveBeenCalledWith('font-size', `${newFontSize}px`);
+    });
+  });
+});