title: go: cannot find main module; see 'go help modules'
body: <p>I recently started using Go. I installed go's extension on vscode and I can use some commands like <code>go run</code> and <code>go build</code> but when I run go test I get the following error:</p>
  <blockquote>
  <p>go: cannot find main module; see 'go help modules'</p>
  </blockquote>
  <p>although I have a <code>*_test.go</code> file.</p>
  <p>When I run go help modules, I get the following output:</p>
  <pre class="lang-none prettyprint-override"><code>Modules are how Go manages dependencies.
  
  A module is a collection of packages that are released, versioned, and
  distributed together. Modules may be downloaded directly from version control
  repositories or from module proxy servers.
  
  For a series of tutorials on modules, see
  https://golang.org/doc/tutorial/create-module.
  
  For a detailed reference on modules, see https://golang.org/ref/mod.
  
  By default, the go command may download modules from https://proxy.golang.org.
  It may authenticate modules using the checksum database at
  https://sum.golang.org. Both services are operated by the Go team at Google.
  The privacy policies for these services are available at
  https://proxy.golang.org/privacy and https://sum.golang.org/privacy,
  respectively.
  
  The go command's download behavior may be configured using GOPROXY, GOSUMDB,
  GOPRIVATE, and other environment variables. See 'go help environment'
  and https://golang.org/ref/mod#private-module-privacy for more information.
  </code></pre>