[StackOverflow/go] Getting "Cannot query module due to -mod=vendor(Go version in go.mod is at least 1.14 and vendor directory exists.)" error when executing unit test

### ROOT CAUSE The error occurs because the Go tool is operating in `-mod=vendor` mode, which requires all dependencies to be present in the vendor directory. If the vendor directory is not up-to-date or the required module is missing, the tool cannot proceed. This is common when running tests in environments where `-mod=vendor` is enforced, such as some CI setups or local development configurations. ### CODE FIX 1. **Update the vendor directory**: ```bash go mod vendor ``` This ensures all dependencies are copied to the `vendor` directory. 2. **Remove the `-mod=vendor` flag** from your test command or environment (if not necessary): ```bash go test ./... # without -mod=vendor ``` Or unset the environment variable if it was set: ```bash unset GOFLAGS # or remove -mod=vendor from your shell's GOFLAGS ``` 3. **If using a CI pipeline**, ensure the `vendor` directory is explicitly copied or the `-mod=vendor` flag is handled correctly in the build steps. This resolves the issue by either keeping the vendor directory updated or switching to a different module resolution mode.