haskell-stack-test: add build target job variable

This change adds support for custom target and adds a
separate build step to better report build failure, as
opposed to a single test failure.

Change-Id: I9e7a5e14b669dcbacd26861595358f6a4c04b585

roles/haskell-stack-test/README.rst

@@ -2,6 +2,10 @@ Run the Haskell stack test command.
 
 **Role Variables**
 
+.. zuul:rolevar:: haskell_stack_target
+
+   The stack target(s) to test.
+
 .. zuul:rolevar:: lts_version
 
    The lts version.

roles/haskell-stack-test/defaults/main.yaml

@@ -1,2 +1,7 @@
+haskell_stack_target: ""
 lts_version: ""
 zuul_work_dir: "{{ zuul.project.src_dir }}"
+
+_stack_resolver_args: "{% if lts_version %}--resolver {{ lts_version }}{% endif %}"
+_stack_build_args: "{{ _stack_resolver_args }} --test --no-run-tests {{ haskell_stack_target }}"
+_stack_test_args: "{{ _stack_resolver_args }} {{ haskell_stack_target }}"

roles/haskell-stack-test/tasks/main.yaml

@@ -1,4 +1,9 @@
-- name: Run stack test
+- name: Run stack build {{ _stack_build_args }}
-  command: "stack {% if lts_version %}--resolver {{ lts_version }}{% endif %} test"
+  command: "stack build {{ _stack_build_args }}"
+  args:
+    chdir: "{{ zuul_work_dir }}"
+
+- name: Run stack test {{ _stack_test_args }}
+  command: "stack test {{ _stack_test_args }}"
   args:
     chdir: "{{ zuul_work_dir }}"

zuul.d/haskell-jobs.yaml

@@ -22,6 +22,10 @@
     description: |
       Run stack test for a Haskell project.
 
+      .. zuul:jobvar:: haskell_stack_target
+
+         The stack target(s) to test.
+
       .. zuul:jobvar:: lts_version
 
          Use the specified lts version.