Add more and unify tests for absent object cases

- Unify test data for nonexistence of an object/string and collection.
- Introduce more test through adding missing test data to existing tests.
- Improve logic for checking absence of values to match tests.
- Add missing tests for absent value validation.
- Update documentation to include shared test functionality.

tests/unit/application/Parser/Script/Compiler/Expressions/Parser/CompositeExpressionParser.spec.ts

@@ -4,18 +4,30 @@ import { IExpression } from '@/application/Parser/Script/Compiler/Expressions/Ex
 import { IExpressionParser } from '@/application/Parser/Script/Compiler/Expressions/Parser/IExpressionParser';
 import { CompositeExpressionParser } from '@/application/Parser/Script/Compiler/Expressions/Parser/CompositeExpressionParser';
 import { ExpressionStub } from '@tests/unit/stubs/ExpressionStub';
+import { itEachAbsentObjectValue } from '@tests/unit/shared/TestCases/AbsentTests';
 
 describe('CompositeExpressionParser', () => {
   describe('ctor', () => {
-    it('throws if one of the parsers is undefined', () => {
+    it('throws if null parsers given', () => {
       // arrange
-      const expectedError = 'undefined leaf';
-      const parsers: readonly IExpressionParser[] = [undefined, mockParser()];
+      const expectedError = 'missing leafs';
+      const parsers = null;
       // act
       const act = () => new CompositeExpressionParser(parsers);
       // assert
       expect(act).to.throw(expectedError);
     });
+    describe('throws if one of the parsers is undefined', () => {
+      itEachAbsentObjectValue((absentValue) => {
+        // arrange
+        const expectedError = 'missing leaf';
+        const parsers: readonly IExpressionParser[] = [absentValue, mockParser()];
+        // act
+        const act = () => new CompositeExpressionParser(parsers);
+        // assert
+        expect(act).to.throw(expectedError);
+      });
+    });
   });
   describe('findExpressions', () => {
     describe('returns result from parsers as expected', () => {