tests: Add basic usage tests

Author: kolayne

tests/basic_usage.bats

@@ -0,0 +1,59 @@
+#!/usr/bin/env bats
+
+basic_test() {
+	# Setup
+	BASE="$(mktemp --directory)"
+	NAME="$(basename "$BASE")"
+	if [ -z "$1" ]; then
+		VOLATILE=false
+	else
+		VOLATILE=true
+	fi
+	docker volume create --driver docker-on-top "$NAME" -o base="$BASE" -o volatile="$VOLATILE"
+
+	# Deferred cleanup
+	trap 'rm -rf "$BASE"; docker volume rm "$NAME"; trap - RETURN' RETURN
+
+	echo 123 > "$BASE"/a
+	echo 456 > "$BASE"/b
+
+	docker run --rm -v "$NAME":/dot alpine:latest \
+		sh -e -c '
+			# Initial data is visible
+			[ "$(cat /dot/a)" = 123 ]
+			[ "$(cat /dot/b)" = 456 ]
+
+			# My file removal is visible to me
+			rm /dot/a
+			[ ! -e /dot/a ]
+
+			# My changes are visible to me
+			echo 789 > /dot/b
+			[ "$(cat /dot/b)" = 789 ]
+
+			# My new files are visible to me
+			echo etc > /dot/c
+			[ "$(cat /dot/c)" = etc ]
+		'
+
+	# Changes are not visible from the host
+	[ "$(cat "$BASE"/a)" = 123 ]
+	[ "$(cat "$BASE"/b)" = 456 ]
+	[ ! -e "$BASE"/c ]
+
+	if $VOLATILE; then
+		# For a volatile volume, changes should not be visible
+		[ "$(docker run --rm -v "$NAME":/dot alpine:latest sh -c 'cat /dot/*')" = "$(echo 123; echo 456)" ]
+	else
+		# For a regular volume, changes should remain
+		[ "$(docker run --rm -v "$NAME":/dot alpine:latest sh -c 'cat /dot/*')" = "$(echo 789; echo etc)" ]
+	fi
+}
+
+@test "Test basic usage" {
+	basic_test
+}
+
+@test "Test volatile basic usage" {
+	basic_test volatile
+}