I have the following project structure
|_typetests
|          |_type.test.ts
|
|
myproj.d.ts
tsconfig.json
My tsconfig.json looks like this:
{
  "compilerOptions": {
      "module": "commonjs",
      "moduleResolution": "node",
      "lib": [
          "es6"
      ],
      "target": "es6",
      "noImplicitAny": true,
      "noImplicitThis": true,
      "strictNullChecks": true,
      "types": [
          "node",
          "mocha"
      ],
      "noEmit": true,
      "forceConsistentCasingInFileNames": true,
      "baseUrl": "./"
  },
  "include": [
      "types/*.test.ts"
  ],
  "exclude": ["node_modules"]
}
If I run ./node_modules/.bin/tsc -p . --traceResolution
Then I can see:
Module name 'myproj' was successfully resolved to '/Users/paulcowan/projects/myproj/myproj.d.ts'. ========
But when I run the following through mocha
./node_modules/.bin/mocha -r ts-node/register types/*.test.ts
Error: Cannot find module 'myproj'