Fix in-tree Eclipse project generation

So far, custom test libraries were not being collected in the classpath.

Test plan:

* Link plugin to gerrit tree
* Add plugin name to `CUSTOM_PLUGINS` and to `CUSTOM_PLUGINS_TEST_DEPS`
  in Gerrit core in `tools/bzl/plugins.bzl`
* Execute ./tools/eclipse/project.py
* Import gerrit project in Eclipse and verify there is no classpath
  errors, events-log plugin source is imported and the custom test
  libraries are referenced.

Change-Id: Ib01076ece88ff81f0027bce2952297e77dfe5855
diff --git a/BUILD b/BUILD
index 8478fd6..5bb0a81 100644
--- a/BUILD
+++ b/BUILD
@@ -23,7 +23,16 @@
     testonly = 1,
     srcs = glob(["src/test/java/**/*.java"]),
     tags = ["events-log"],
-    deps = PLUGIN_DEPS + PLUGIN_TEST_DEPS + [
+    deps = [
+        ":events-log__plugin_test_deps",
+    ],
+)
+
+java_library(
+    name = "events-log__plugin_test_deps",
+    testonly = 1,
+    visibility = ["//visibility:public"],
+    exports = PLUGIN_DEPS + PLUGIN_TEST_DEPS + [
         ":events-log__plugin",
         "@mockito//jar",
     ],
diff --git a/src/main/resources/Documentation/build.md b/src/main/resources/Documentation/build.md
index 6c1ba49..fddf172 100644
--- a/src/main/resources/Documentation/build.md
+++ b/src/main/resources/Documentation/build.md
@@ -29,8 +29,9 @@
 ```
 
 This project can be imported into the Eclipse IDE.
-Add the plugin name to the `CUSTOM_PLUGINS` set in
-Gerrit core in `tools/bzl/plugins.bzl`, and execute:
+Add the plugin name to the `CUSTOM_PLUGINS` and to the
+`CUSTOM_PLUGINS_TEST_DEPS` set in Gerrit core in
+`tools/bzl/plugins.bzl`, and execute:
 
 ```
   ./tools/eclipse/project.py