Add data file for early data input

Signed-off-by: Jerry Yu <jerry.h.yu@arm.com>
diff --git a/tests/data_files/early_data.txt b/tests/data_files/early_data.txt
new file mode 100644
index 0000000..f0084c3
--- /dev/null
+++ b/tests/data_files/early_data.txt
@@ -0,0 +1,3 @@
+EarlyData context: line 0                                                    lf
+EarlyData context: line 1                                                    lf
+EarlyData context: If it appear, that means early_data success