[ADF-1920] diagram button enabling and disabling correctly

lib/process-services/process-list/components/process-instance-details.component.html

@@ -9,7 +9,7 @@
             (showProcessDiagram)="onShowProcessDiagram($event)">
         </adf-process-instance-header>
 
-        <button class="adf-in-medias-res-button" mat-button id="show-diagram-button" type="button" mat-button mat-raised-button [disabled]="isDiagramDisabled()" (click)="onShowProcessDiagram(processInstanceId)">{{ 'ADF_PROCESS_LIST.DETAILS.BUTTON.SHOW_DIAGRAM' | translate }}</button>
+        <button class="adf-in-medias-res-button" mat-button id="show-diagram-button" type="button" mat-button mat-raised-button [disabled]="!isRunning()" (click)="onShowProcessDiagram(processInstanceId)">{{ 'ADF_PROCESS_LIST.DETAILS.BUTTON.SHOW_DIAGRAM' | translate }}</button>
 
         <mat-card>
             <mat-card-content>

lib/process-services/process-list/components/process-instance-details.component.spec.ts

@@ -138,6 +138,35 @@ describe('ProcessInstanceDetailsComponent', () => {
             let buttonEl = fixture.debugElement.query(By.css('[data-automation-id="header-status"] button'));
             expect(buttonEl).not.toBeNull();
         });
+
+        describe('Diagram', () => {
+
+            it('should diagram button be enabled if the process is running', () => {
+                component.processInstanceDetails = new ProcessInstance({
+                    ended: null
+                });
+                fixture.detectChanges();
+
+                fixture.whenStable().then(() => {
+                    let diagramButton = fixture.debugElement.query(By.css('#show-diagram-button'));
+                    expect(diagramButton).not.toBeNull();
+                    expect(diagramButton.nativeElement.disabled).toBe(false);
+                });
             });
 
+            it('should diagram button be enabled if the process is running', () => {
+                component.processInstanceDetails = new ProcessInstance({
+                    ended: new Date()
+                });
+
+                fixture.detectChanges();
+
+                fixture.whenStable().then(() => {
+                    let diagramButton = fixture.debugElement.query(By.css('#show-diagram-button'));
+                    expect(diagramButton).not.toBeNull();
+                    expect(diagramButton.nativeElement.disabled).toBe(true);
+                });
+            });
+        });
+    });
 });

lib/process-services/process-list/components/process-instance-details.component.ts

@@ -103,10 +103,6 @@ export class ProcessInstanceDetailsComponent implements OnChanges {
         return this.processInstanceDetails && !this.processInstanceDetails.ended;
     }
 
-    isDiagramDisabled(): boolean {
-        return !this.isRunning() ? true : undefined;
-    }
-
     cancelProcess() {
         this.activitiProcess.cancelProcess(this.processInstanceId).subscribe(
             (data) => {