test(integration): add tests for self-injections providers

integration/injector/e2e/injector.spec.ts

@@ -1,7 +1,10 @@
 import { RuntimeException } from '@nestjs/core/errors/exceptions/runtime.exception';
+import { UnknownDependenciesException } from '@nestjs/core/errors/exceptions/unknown-dependencies.exception';
 import { UnknownExportException } from '@nestjs/core/errors/exceptions/unknown-export.exception';
 import { Test } from '@nestjs/testing';
 import { expect } from 'chai';
+import * as chai from 'chai';
+import * as chaiAsPromised from 'chai-as-promised';
 import {
   DYNAMIC_TOKEN,
   DYNAMIC_VALUE,
@@ -9,6 +12,13 @@ import {
 } from '../src/dynamic/dynamic.module';
 import { ExportsModule } from '../src/exports/exports.module';
 import { InjectModule } from '../src/inject/inject.module';
+import { InjectSameNameModule } from '../src/inject/inject-same-name.module';
+import {
+  SelfInjectionProviderModule,
+  SelfInjectionProviderCustomTokenModule,
+  SelfInjectionForwardProviderModule,
+} from '../src/self-injection/self-injection-provider.module';
+chai.use(chaiAsPromised);
 
 describe('Injector', () => {
   describe('when "providers" and "exports" properties are inconsistent', () => {
@@ -24,6 +34,16 @@ describe('Injector', () => {
     });
   });
 
+  describe("When class injects a provider with the same as class's name", () => {
+    it('should compile with success', async () => {
+      const builder = Test.createTestingModule({
+        imports: [InjectSameNameModule],
+      });
+
+      await expect(builder.compile()).to.eventually.be.fulfilled;
+    });
+  });
+
   describe('when Nest cannot resolve dependencies', () => {
     it(`should fail with "RuntimeException"`, async () => {
       try {
@@ -35,6 +55,42 @@ describe('Injector', () => {
         expect(err).to.be.instanceof(RuntimeException);
       }
     });
+
+    describe('due to self-injection providers', () => {
+      it('should fail with "UnknownDependenciesException" due to self-injection via same class reference', async () => {
+        const builder = Test.createTestingModule({
+          imports: [SelfInjectionProviderModule],
+        });
+
+        await expect(
+          builder.compile(),
+        ).to.eventually.be.rejected.and.be.an.instanceOf(
+          UnknownDependenciesException,
+        );
+      });
+      it('should fail with "UnknownDependenciesException" due to self-injection via forwardRef to the same class reference', async () => {
+        const builder = Test.createTestingModule({
+          imports: [SelfInjectionForwardProviderModule],
+        });
+
+        await expect(
+          builder.compile(),
+        ).to.eventually.be.rejected.and.be.an.instanceOf(
+          UnknownDependenciesException,
+        );
+      });
+      it('should fail with "UnknownDependenciesException" due to self-injection via custom provider', async () => {
+        const builder = Test.createTestingModule({
+          imports: [SelfInjectionProviderCustomTokenModule],
+        });
+
+        await expect(
+          builder.compile(),
+        ).to.eventually.be.rejected.and.be.an.instanceOf(
+          UnknownDependenciesException,
+        );
+      });
+    });
   });
 
   describe('when dynamic module', () => {

integration/injector/src/inject/inject-same-name.module.ts

@@ -0,0 +1,16 @@
+import { Module, Injectable, Inject } from '@nestjs/common';
+
+@Injectable()
+class CoreService {
+  constructor(@Inject(CoreService.name) private readonly coreService: any) {}
+}
+
+@Module({
+  providers: [
+    {
+      provide: CoreService.name,
+      useValue: 'anything',
+    },
+  ],
+})
+export class InjectSameNameModule {}

integration/injector/src/self-injection/self-injection-provider.module.ts

@@ -0,0 +1,40 @@
+import { Module, Injectable, Inject, forwardRef } from '@nestjs/common';
+
+@Injectable()
+class ServiceInjectingItself {
+  constructor(private readonly coreService: ServiceInjectingItself) {}
+}
+
+@Injectable()
+class ServiceInjectingItselfForwared {
+  constructor(
+    @Inject(forwardRef(() => ServiceInjectingItself))
+    private readonly coreService: ServiceInjectingItself,
+  ) {}
+}
+
+@Injectable()
+class ServiceInjectingItselfViaCustomToken {
+  constructor(@Inject('AnotherToken') private readonly coreService: any) {}
+}
+
+@Module({
+  providers: [ServiceInjectingItself],
+})
+export class SelfInjectionProviderModule {}
+
+@Module({
+  providers: [ServiceInjectingItselfForwared],
+})
+export class SelfInjectionForwardProviderModule {}
+
+@Module({
+  providers: [
+    ServiceInjectingItselfViaCustomToken,
+    {
+      provide: 'AnotherToken',
+      useClass: ServiceInjectingItselfViaCustomToken,
+    },
+  ],
+})
+export class SelfInjectionProviderCustomTokenModule {}