--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/entai/entai_test.go	Sat Oct 01 11:16:31 2016 +0900
@@ -0,0 +1,45 @@
+/****************************************************************************/
+/* Entai_test.go ( ver 0.1 )                                                */
+/*                                    Last Change: 2016-10-01 Sat 09:21:21. */
+/****************************************************************************/
+
+package entai
+
+import (
+    "time"
+    "testing"
+)
+
+func TestEntai( t *testing.T ) {
+
+    var tests = []struct {
+        due  string
+        paid string
+        tax  int
+        want int
+    }{
+        { "20160731", "20160930", 29000,    0 },
+        { "20150731", "20160930", 29000, 2900 },
+        { "20140731", "20160730", 29000, 5700 },
+    }
+
+    for _, test := range tests {
+        test01( test.due, test.paid, test.tax, test.want, t )
+    }
+}
+
+func test01( due, paid string, tax, want int, t *testing.T ) {
+
+    var e Entai
+
+    layout := "20060102"
+    d, _ := time.Parse( layout, due )
+    p, _ := time.Parse( layout, paid )
+
+    e.Set( d, p, tax )
+    got, _ := e.Result()
+    if got != want {
+        t.Errorf( "want %v, but %v\n", want, got )
+    }
+}
+