introduce some bats tests

test/stub.bats

@@ -0,0 +1,28 @@
+#!/usr/bin/env bats
+
+# this is the "code under test"
+# it would normally be in another file
+format_date() {
+  date -r 222
+}
+
+setup() {
+  load '../load'
+
+  _DATE_ARGS='-r 222'
+  stub date \
+      "${_DATE_ARGS} : echo 'I am stubbed!'" \
+      "${_DATE_ARGS} : echo 'Wed Dec 31 18:03:42 CST 1969'"
+}
+
+teardown() {
+  unstub date
+}
+
+@test "date format util formats date with expected arguments" {
+  result="$(format_date)"
+  [ "$result" == 'I am stubbed!' ]
+
+  result="$(format_date)"
+  [ "$result" == 'Wed Dec 31 18:03:42 CST 1969' ]
+}

test/stub_fct.bats

@@ -0,0 +1,37 @@
+#!/usr/bin/env bats
+
+# this is the "code under test"
+# it would normally be in another file
+format_date() {
+  date -r 222
+}
+
+# this is a function used in stub return evaluation
+function my_test_fct()
+{
+    echo "This is my final stub return, receiving arguments: $*"
+}
+# it must be exported in the script to be accessible to its childs
+export -f my_test_fct
+
+setup() {
+  # Load library
+  load '../load'
+
+  _DATE_ARGS='-r 222'
+  stub date \
+      "${_DATE_ARGS} : echo 'I am stubbed!'" \
+      "${_DATE_ARGS} : my_test_fct \$*"
+}
+
+teardown() {
+  unstub date
+}
+
+@test "date format util formats date with expected arguments" {
+  result="$(format_date)"
+  [ "$result" == 'I am stubbed!' ]
+
+  result="$(format_date)"
+  [ "$result" == "This is my final stub return, receiving arguments: -r 222" ]
+}