split up unit-tests and use 4 containers (they're free)

tests.mk

@@ -61,7 +61,11 @@ lint:
 
 unit-tests:
 	@echo running unit tests...
+ifndef UNIT_TEST_BATCH
 	@$(QUIET) bats tests/unit
+else
+	@$(QUIET) ./tests/ci/unit_test_runner.sh $$UNIT_TEST_BATCH
+endif
 
 deploy-test-clojure:
 	@echo deploying config app...

tests/ci/parallel_runner.sh

@@ -2,16 +2,21 @@
 
 case "$CIRCLE_NODE_INDEX" in
   0)
-    echo "=====> make unit-tests"
+    echo "=====> make unit-tests (1/2)"
-    sudo -E make -e unit-tests
+    sudo -E UNIT_TEST_BATCH=1 make -e unit-tests
     ;;
 
   1)
+    echo "=====> make unit-tests (2/2)"
+    sudo -E UNIT_TEST_BATCH=2 make -e unit-tests
+    ;;
+
+  2)
     echo "=====> make deploy-tests (buildstep release)"
     sudo -E make -e deploy-tests
     ;;
 
-  2)
+  3)
     echo "=====> make deploy-tests (buildstep master)"
     docker rmi -f progrium/buildstep && \
     sudo -E BUILD_STACK=true make -e stack && \

tests/ci/unit_test_runner.sh

@@ -0,0 +1,37 @@
+#!/usr/bin/env bash
+
+is_number() {
+  local NUMBER=$1; local NUM_RE='^[0-9]+$'
+  if [[ $NUMBER =~ $NUM_RE ]];then
+    return 0
+  else
+    return 1
+  fi
+}
+
+usage() {
+  echo "usage: $0 1|2"
+  exit 0
+}
+
+BATCH_NUM="$1"
+is_number $BATCH_NUM || usage
+
+TESTS=( $(find $(dirname $0)/../unit -maxdepth 1 -name "*.bats") )
+HALF_TESTS=$(( ${#TESTS[@]} / 2 ))
+FIRST_HALF=${TESTS[@]:0:${HALF_TESTS}}
+LAST_HALF=${TESTS[@]:${HALF_TESTS}:${#TESTS[@]}}
+
+case "$BATCH_NUM" in
+  1)
+    bats $FIRST_HALF
+  ;;
+
+  2)
+    bats $LAST_HALF
+  ;;
+
+  *)
+    usage
+  ;;
+esac