diff --git a/projects/http-loader/src/lib/http-loader.ts b/projects/http-loader/src/lib/http-loader.ts
index 0bb3c53..fd9bc53 100644
--- a/projects/http-loader/src/lib/http-loader.ts
+++ b/projects/http-loader/src/lib/http-loader.ts
@@ -1,9 +1,16 @@
-import {HttpClient} from "@angular/common/http";
 import {TranslateLoader, TranslationObject} from "@ngx-translate/core";
+import {HttpClient} from "@angular/common/http";
+import {Inject, Injectable} from "@angular/core";
 import {Observable} from 'rxjs';
 
+@Injectable()
 export class TranslateHttpLoader implements TranslateLoader {
-  constructor(private http: HttpClient, public prefix = "/assets/i18n/", public suffix = ".json") {}
+  constructor(
+    private http: HttpClient,
+    @Inject(String) public prefix:string = "/assets/i18n/",
+    @Inject(String) public suffix:string = ".json"
+  )
+  {}
 
   /**
    * Gets the translations from the server
diff --git a/projects/ngx-translate/src/lib/missing-translation-handler.spec.ts b/projects/ngx-translate/src/lib/missing-translation-handler.spec.ts
index 6e64bf8..c8d8c42 100644
--- a/projects/ngx-translate/src/lib/missing-translation-handler.spec.ts
+++ b/projects/ngx-translate/src/lib/missing-translation-handler.spec.ts
@@ -7,11 +7,12 @@ import {
   TranslateService, Translation,
   TranslationObject
 } from "../public-api";
-import {Type} from "@angular/core";
+import {Injectable, Type} from "@angular/core";
 
 let translations: TranslationObject = {"TEST": "This is a test"};
 const fakeTranslation: TranslationObject = {"NOT_USED": "not used"};
 
+@Injectable()
 class FakeLoader implements TranslateLoader {
   getTranslation(lang: string): Observable<TranslationObject> {
     if (lang === 'fake') {
@@ -26,6 +27,7 @@ describe('MissingTranslationHandler', () => {
   let translate: TranslateService;
   let missingTranslationHandler: MissingTranslationHandler;
 
+  @Injectable()
   class Missing implements MissingTranslationHandler {
     handle(params: MissingTranslationHandlerParams) {
       void params;
@@ -33,6 +35,7 @@ describe('MissingTranslationHandler', () => {
     }
   }
 
+  @Injectable()
   class MissingObs implements MissingTranslationHandler {
     handle(params: MissingTranslationHandlerParams): Observable<Translation> {
       return of(`handled: ${params.key}`);
diff --git a/projects/ngx-translate/src/lib/translate.compiler.spec.ts b/projects/ngx-translate/src/lib/translate.compiler.spec.ts
index 91bbb19..b6e258f 100644
--- a/projects/ngx-translate/src/lib/translate.compiler.spec.ts
+++ b/projects/ngx-translate/src/lib/translate.compiler.spec.ts
@@ -10,9 +10,11 @@ import {
   Translation,
   provideTranslateService
 } from "../public-api";
+import {Injectable} from "@angular/core";
 
 const translations: TranslationObject = {LOAD: 'This is a test'};
 
+@Injectable()
 class FakeLoader implements TranslateLoader {
   getTranslation(lang: string): Observable<TranslationObject> {
     void lang;
diff --git a/projects/ngx-translate/src/lib/translate.loader.spec.ts b/projects/ngx-translate/src/lib/translate.loader.spec.ts
index 3716f4a..2bd4f54 100644
--- a/projects/ngx-translate/src/lib/translate.loader.spec.ts
+++ b/projects/ngx-translate/src/lib/translate.loader.spec.ts
@@ -8,9 +8,11 @@ import {
   Translation,
   provideTranslateService
 } from "../public-api";
+import {Injectable} from "@angular/core";
 
 const translations: TranslationObject = {"TEST": "This is a test"};
 
+@Injectable()
 class FakeLoader implements TranslateLoader {
   getTranslation(): Observable<TranslationObject> {
     return of(translations);
diff --git a/projects/ngx-translate/src/lib/translate.pipe-modules.spec.ts b/projects/ngx-translate/src/lib/translate.pipe-modules.spec.ts
index 652d79d..c213df6 100644
--- a/projects/ngx-translate/src/lib/translate.pipe-modules.spec.ts
+++ b/projects/ngx-translate/src/lib/translate.pipe-modules.spec.ts
@@ -49,6 +49,7 @@ class AppComponent {
 
 let translations: TranslationObject = {"TEST": "This is a test"};
 
+@Injectable()
 class FakeLoader implements TranslateLoader {
   getTranslation(lang: string): Observable<TranslationObject> {
     void lang;
diff --git a/projects/ngx-translate/src/lib/translate.pipe-standalone.spec.ts b/projects/ngx-translate/src/lib/translate.pipe-standalone.spec.ts
index 9f82fa9..e4591d6 100644
--- a/projects/ngx-translate/src/lib/translate.pipe-standalone.spec.ts
+++ b/projects/ngx-translate/src/lib/translate.pipe-standalone.spec.ts
@@ -58,6 +58,7 @@ class AppComponent {
 
 let translations: TranslationObject = {"TEST": "This is a test"};
 
+@Injectable()
 class FakeLoader implements TranslateLoader {
   getTranslation(lang: string): Observable<TranslationObject> {
     void lang;
@@ -65,12 +66,14 @@ class FakeLoader implements TranslateLoader {
   }
 }
 
+@Injectable()
 class DelayedFrenchLoader implements TranslateLoader {
   getTranslation(lang: string): Observable<TranslationObject> {
     return lang === 'fr' ? timer(10).pipe(map(() => translations)) : of(translations);
   }
 }
 
+@Injectable()
 class MissingObs implements MissingTranslationHandler {
   handle(params: MissingTranslationHandlerParams): Translation|Observable<Translation> {
     return timer(1).pipe(map(() => `handled: ${params.key}`));