[SUREFIRE-2004] Empty report for single-module project with 'aggregate=true'

**[Alexander Kriegisch](https://issues.apache.org/jira/secure/ViewProfile.jspa?name=kriegaex)** opened **[SUREFIRE-2004](https://issues.apache.org/jira/browse/SUREFIRE-2004?redirect=false)** and commented

Using either `-Daggregate=true` on CLI or `true` in the plugin configuration leads to an empty report (i.e. zero tests reported) when e.g. executing

```none
mvn -Dmaven.test.failure.ignore=true -Daggregate=true clean verify surefire-report:report-only
```

in the context of a single-module project. As soon as I make the root module pom-packaged and move the tests to into a child module, the aggregate report works.

FYI, if I do not define the plugin and its version in my POM at all, the default version 2.4 used by Maven on my workstation has the same problem, so this does not seem to be a 3.0.0-M5 issue only.

---

Background info about how and why I actually stumbled across this problem: I have an OSS multi-module project with lots of expensive UI tests. The full build can take 2.5 hours. I wanted to test a few CLI settings before creating an additional GitHub CI build workflow which can be run on demand and always runs all tests in all modules (ignoring errors and failures), no matter what. In the end, it is supposed to create a single-file aggregate HTML report which can easily be attached to the build and later is available for download, if the user so chooses in order to analyse failing tests comfortable and without having to scroll through build logs. You get the picture, I guess. In the original project, there is a pom-packaged root POM, so the problem described in this issue does not occur there. I simply created a single-module dummy project in order to verify the effect of certain build options quickly and not having to wait for the slow original build to finish. Eventually, I noticed the issue described above.

---

**Affects:** 2.4, 3.0.0-M5

Reproduce the issue with a single-module project using `mvn -Dmaven.test.failure.ignore=true -Daggregate=true clean verify surefire-report:report-only`, then compare it with a root POM and child-module setup. The work is done when the single-module aggregate report includes the executed tests instead of reporting zero tests.

Written by the indexing model from the issue text.