Use rules_erlang 3.13.1

This version of rules_erlang adds coverage support

Bazel has sort of standardized on lcov for coverage, so that is what
we use.

Example:
1. `bazel coverage //deps/rabbit:eunit -t-`
2. `genhtml --output genhtml "$(bazel info
output_path)/_coverage/_coverage_report.dat"`
3. `open genhtml/index.html`

Multiple tests can be run with results aggregated, i.e. `bazel
coverage //deps/rabbit:all -t-`

Running coverage with RBE has a lot of caveats,
https://bazel.build/configure/coverage#remote-execution, so the above
commands won't work as is with RBE.

.bazelrc

@@ -13,6 +13,8 @@ build --flag_alias=test_build=//:enable_test_build
 
 build --test_timeout=7200
 
+build --combined_report=lcov
+
 build:buildbuddy --bes_results_url=https://app.buildbuddy.io/invocation/
 build:buildbuddy --bes_backend=grpcs://remote.buildbuddy.io
 build:buildbuddy --remote_cache=grpcs://remote.buildbuddy.io

.gitignore

@@ -72,6 +72,7 @@ rebar3.crashdump
 *.lock
 
 /logs/
+/genhtml/
 
 /topic-branch-scratch/
 

MODULE.bazel

@@ -31,7 +31,7 @@ bazel_dep(
 
 bazel_dep(
     name = "rules_erlang",
-    version = "3.12.0",
+    version = "3.13.1",
 )
 
 bazel_dep(

deps/rabbit/BUILD.bazel

@@ -1324,4 +1324,7 @@ eunit(
     ],
     erl_extra_args = [ENABLE_FEATURE_MAYBE_EXPR],
     target = ":test_erlang_app",
+    test_env = {
+        "COVERDATA_TO_LCOV_APPS_DIRS": "deps:deps/rabbit/apps",
+    },
 )

rabbitmq.bzl

@@ -175,12 +175,14 @@ def rabbitmq_suite(
         deps = [],
         runtime_deps = [],
         **kwargs):
+    app_name = native.package_name().rpartition("/")[-1]
     # suite_name exists in the underying ct_test macro, but we don't
     # want to use the arg in rabbitmq-server, for the sake of clarity
     if suite_name != None:
         fail("rabbitmq_suite cannot be called with a suite_name attr")
     ct_test(
         name = name,
+        app_name = app_name,
         compiled_suites = [":{}_beam_files".format(name)] + additional_beam,
         ct_run_extra_args = [ENABLE_FEATURE_MAYBE_EXPR],
         data = native.glob(["test/{}_data/**/*".format(name)]) + data,
@@ -221,6 +223,7 @@ def rabbitmq_integration_suite(
         deps = [],
         runtime_deps = [],
         **kwargs):
+    app_name = native.package_name().rpartition("/")[-1]
     # suite_name exists in the underying ct_test macro, but we don't
     # want to use the arg in rabbitmq-server, for the sake of clarity
     if suite_name != None:
@@ -239,6 +242,7 @@ def rabbitmq_integration_suite(
 
     ct_test(
         name = name,
+        app_name = app_name,
         suite_name = name,
         compiled_suites = [":{}_beam_files".format(name)] + additional_beam,
         tags = tags + [STARTS_BACKGROUND_BROKER_TAG],