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.

src/application/Context/ApplicationContext.ts

@@ -27,12 +27,12 @@ export class ApplicationContext implements IApplicationContext {
     initialContext: OperatingSystem,
   ) {
     validateApp(app);
-    assertInRange(initialContext, OperatingSystem);
     this.states = initializeStates(app);
     this.changeContext(initialContext);
   }
 
   public changeContext(os: OperatingSystem): void {
+    assertInRange(os, OperatingSystem);
     if (this.currentOs === os) {
       return;
     }
@@ -51,7 +51,7 @@ export class ApplicationContext implements IApplicationContext {
 
 function validateApp(app: IApplication) {
   if (!app) {
-    throw new Error('undefined app');
+    throw new Error('missing app');
   }
 }
 

src/application/Context/ApplicationContextFactory.ts

@@ -11,8 +11,8 @@ export async function buildContext(
   factory: IApplicationFactory = ApplicationFactory.Current,
   environment = Environment.CurrentEnvironment,
 ): Promise<IApplicationContext> {
-  if (!factory) { throw new Error('undefined factory'); }
-  if (!environment) { throw new Error('undefined environment'); }
+  if (!factory) { throw new Error('missing factory'); }
+  if (!environment) { throw new Error('missing environment'); }
   const app = await factory.getApp();
   const os = getInitialOs(app, environment);
   return new ApplicationContext(app, os);

src/application/Context/State/Code/ApplicationCode.ts

@@ -21,9 +21,9 @@ export class ApplicationCode implements IApplicationCode {
     private readonly scriptingDefinition: IScriptingDefinition,
     private readonly generator: IUserScriptGenerator = new UserScriptGenerator(),
   ) {
-    if (!userSelection) { throw new Error('userSelection is null or undefined'); }
-    if (!scriptingDefinition) { throw new Error('scriptingDefinition is null or undefined'); }
-    if (!generator) { throw new Error('generator is null or undefined'); }
+    if (!userSelection) { throw new Error('missing userSelection'); }
+    if (!scriptingDefinition) { throw new Error('missing scriptingDefinition'); }
+    if (!generator) { throw new Error('missing generator'); }
     this.setCode(userSelection.selectedScripts);
     userSelection.changed.on((scripts) => {
       this.setCode(scripts);

src/application/Context/State/Code/Generation/UserScriptGenerator.ts

@@ -17,8 +17,8 @@ export class UserScriptGenerator implements IUserScriptGenerator {
     selectedScripts: ReadonlyArray<SelectedScript>,
     scriptingDefinition: IScriptingDefinition,
   ): IUserScript {
-    if (!selectedScripts) { throw new Error('undefined scripts'); }
-    if (!scriptingDefinition) { throw new Error('undefined definition'); }
+    if (!selectedScripts) { throw new Error('missing scripts'); }
+    if (!scriptingDefinition) { throw new Error('missing definition'); }
     if (!selectedScripts.length) {
       return { code: '', scriptPositions: new Map<SelectedScript, ICodePosition>() };
     }