Add csv format test data

test/README.md

@@ -0,0 +1,26 @@
+# Test Data
+
+Each directory has two sets of test data, both in csv format. The last column of each line
+represents the rank of the test case, and the other columns are the card input.
+
+In the `string_input_tests.csv` files, the card inputs are using string format, while in the
+`id_input_tests.csv` files, the inputs are [Card Id](../cpp/#cardid) format.
+
+For example, if we look at the file `five/string_input_tests.csv`, it has six columns.
+The first five columns are the five different cards, and the last column is the rank of the
+given five cards.
+
+```bash
+card_1,card_2,card_3,card_4,card_5,rank
+2C,2D,2H,2S,3C,166
+2C,2D,2H,2S,3D,166
+2C,2D,2H,2S,3H,166
+2C,2D,2H,2S,3S,166
+2C,2D,2H,2S,4C,165
+2C,2D,2H,2S,4D,165
+2C,2D,2H,2S,4H,165
+2C,2D,2H,2S,4S,165
+2C,2D,2H,2S,5C,164
+```
+
+The cards in the first test case are: 2C, 2D, 2H, 2S, and 3C, which ranks at 166.