Rewrite and expand EUnit suite; run unit tests in CI from shared test image. Refs EventHub/EventHubBack#36 [skip ci]

docker/ApiTests.Dockerfile

@@ -1,4 +1,4 @@
-# API common_test — только builder-стадия (полный OTP + компиляторы).
+# EUnit + API common_test — один builder-образ, разные CMD в CI.
 ARG ERLANG_BUILDER_IMAGE=git.sabilin.com/eventhub/erlang-builder:latest
 FROM ${ERLANG_BUILDER_IMAGE}
 
@@ -7,9 +7,12 @@ WORKDIR /app
 COPY rebar.config ./
 COPY include/ include/
 COPY src/ src/
+COPY test/unit/ test/unit/
 COPY test/api_*_SUITE.erl test/
 COPY test/api/ test/api/
 
-RUN rebar3 compile
+# default profile: CT (test/api); test profile: EUnit (test/unit)
+RUN rebar3 compile && rebar3 as test compile
 
+# По умолчанию CT; для eunit: docker run … rebar3 eunit --sname ci_eunit --verbose
 CMD ["rebar3", "ct", "--sname", "ci_api_test", "-v"]