tests: improve tests on slug_ref function

tests/slug_ref.bats

@@ -0,0 +1,55 @@
+#!/usr/bin/env bats
+
+@test "Slug master branch" {
+  test_sluf_ref \
+    "refs/heads/master" \
+    "master"
+}
+
+@test "Slug a feature branch" {
+  test_sluf_ref \
+    "refs/heads/feat/new_feature" \
+    "new-feature"
+}
+
+@test "Slug a fix branch" {
+  test_sluf_ref \
+    "refs/heads/fix/issue_number" \
+    "issue-number"
+}
+
+@test "Slug a simple tag" {
+  test_sluf_ref \
+    "refs/tags/v1.0.0" \
+    "v1-0-0"
+}
+
+@test "Slug a complex tag" {
+  test_sluf_ref \
+    "refs/tags/product@1.0.0-rc.2" \
+    "product-1-0-0-rc-2"
+}
+
+@test "Slug a reference with upper case letters" {
+  test_sluf_ref \
+    "refs/heads/New_Awesome_Product" \
+    "new-awesome-product"
+}
+
+@test "Slug a very long name" {
+  test_sluf_ref \
+    "refs/heads/an-awesome-Feature-Very-Very-Very-Very-Very-Very-Very-Long-moreThan63Characters" \
+    "an-awesome-feature-very-very-very-very-very-very-very-long-more"
+}
+
+# Load sluf_ref function
+source entrypoint.sh > /dev/null 2>&1
+
+test_sluf_ref() {
+  given="${1}"
+  expected="${2}"
+
+  actual="$(slug_ref \"${given}\")"
+  echo "expected : [${expected}], actual : [${actual}]"
+  [ "${actual}" == "${expected}" ]
+}