Error when I try to test with NestJS, Jest and GraphQLFederationModule - jestjs

Question

When I try to test with this module it gives me the following error:
FAIL test/test.e2e-spec.ts (28.561s)
AppController (e2e)
× test (4555ms)
● AppController (e2e) › test
Configuration error:
Could not locate module ./src/index-minimal mapped as:
C:\absolute\path\server\company\src\$1.
Please check your configuration for these entries:
{
"moduleNameMapper": {
"/src\/(.*)/": "C:\absolute\path\server\company\src\$1"
},
"resolver": undefined
}
at createNoMappedModuleFoundError (../node_modules/jest-resolve/build/index.js:545:17)
at Object.<anonymous> (../node_modules/#apollo/protobufjs/minimal.js:4:18)
The jest config file is:
{
"moduleFileExtensions": ["js", "json", "ts"],
"rootDir": ".",
"testRegex": ".e2e-spec.ts$",
"transform": {
"^.+\\.(t|j)s$": "ts-jest"
},
"testEnvironment": "node",
"moduleDirectories": ["node_modules", "src"],
"moduleNameMapper": {
"src/(.*)": "<rootDir>/../src/$1"
}
}
The app.module file:
#Module({
imports: [
...,
GraphQLFederationModule.forRootAsync({
imports: [CustomConfigModule],
inject: [EnvironmentStateService],
useFactory: (environmentStateService: EnvironmentStateService) => ({
introspection: environmentStateService.isDev,
debug: environmentStateService.isDev,
playground: environmentStateService.isDev,
autoSchemaFile: true,
tracing: environmentStateService.isDev,
}),
}),
...,
],
})
export class AppModule {}
When I try the following settings in app.module it works correctly:
#Module({
imports: [
...,
GraphQLModule.forRootAsync({
imports: [CustomConfigModule],
inject: [EnvironmentStateService],
useFactory: (environmentStateService: EnvironmentStateService) => ({
introspection: environmentStateService.isDev,
debug: environmentStateService.isDev,
playground: environmentStateService.isDev,
autoSchemaFile: true,
tracing: environmentStateService.isDev,
}),
}),
...,
],
})
export class AppModule {}
I have been reviewing the file where it gives me the error and I find the following protobufjs code in node_modules (minimal.js):
// minimal library entry point.
"use strict";
module.exports = require("./src/index-minimal");
Does anyone know what may be happening? Thank you!

Answer 1

I have changed my paths in the form: "src/folder/..." to "#App/folder/..." and in the end it works fine, but I'm left curious why this happens and if there is any solution To this, I will be attentive to possible solutions and recommendations, thank you very much!
In case someone wants to see the solution, it is as follows:
The tsconfig.json:
{
"compilerOptions": {
...
"baseUrl": "./",
"paths": {
"#App/*": ["src/*"]
},
...
},
...
}
The jest config file:
{
"moduleFileExtensions": ["js", "json", "ts"],
"rootDir": ".",
"testRegex": ".e2e-spec.ts$",
"transform": {
"^.+\\.(t|j)s$": "ts-jest"
},
"testEnvironment": "node",
"moduleNameMapper": {
"^#App/(.*)$": "<rootDir>/../src/$1"
}
}
Regards!

Answer 2

I ran into the same problem, my jest-e2e.json file was also similar
"moduleNameMapper": {
"src/(.*)": "<rootDir>/../src/$1"
}
The error Could not locate module ./src/index-minimal mapped as: ... occurred because the minimal.js file in protobufjs tries to import ./src/index-minimal but our Jest runner remaps the file path name to <rootDir>/../src/$1 so protobufjs threw an error because it cannot find the ./src/index-minimal.js file.
The solution is to leave src/index-minimal alone, so we don't remap its name. I added the following line to the moduleNameMapper field in jest-e2e.json and it solved the issue
"moduleNameMapper": {
"src/index-minimal": "./src/index-minimal",
"src/(.*)": "<rootDir>/../src/$1"
}
Just note not to create a file named index-minimal in your src folder because Jest will fail to map the filename properly.