diff --git a/tests/cases/f-echo.cases b/tests/cases/f-echo.cases
new file mode 100644
index 0000000..b8abdd1
--- /dev/null
+++ b/tests/cases/f-echo.cases
@@ -0,0 +1,14 @@
+1
+2
+
+2
+-2
+
+-1 
+1
+
+10
+10
+
+12
+12
\ No newline at end of file