refactor: Create IdField class - will eventually search Task.id

Author: claremacrae

src/Query/Filter/IdField.ts

@@ -0,0 +1,16 @@
+import { Field } from './Field';
+import { FilterOrErrorMessage } from './FilterOrErrorMessage';
+
+export class IdField extends Field {
+    public createFilterOrErrorMessage(line: string): FilterOrErrorMessage {
+        return FilterOrErrorMessage.fromError(line, 'Not yet implemented');
+    }
+
+    public fieldName(): string {
+        return 'id';
+    }
+
+    protected filterRegExp(): RegExp | null {
+        return null;
+    }
+}

tests/Query/Filter/IdField.test.ts

@@ -0,0 +1,20 @@
+import { testFilter } from '../../TestingTools/FilterTestHelpers';
+import { TaskBuilder } from '../../TestingTools/TaskBuilder';
+import { IdField } from '../../../src/Query/Filter/IdField';
+
+describe('id', () => {
+    const idField = new IdField();
+
+    it('should supply field name', () => {
+        expect(idField.fieldName()).toEqual('id');
+    });
+
+    it.failing('by id presence', () => {
+        // Arrange
+        const filter = new IdField().createFilterOrErrorMessage('has id');
+
+        // Act, Assert
+        testFilter(filter, new TaskBuilder().id(''), false);
+        testFilter(filter, new TaskBuilder().id('abcdef'), true);
+    });
+});