diff --git a/timeutils/json_test.go b/timeutils/json_test.go
new file mode 100644
index 0000000..1ff3331
--- /dev/null
+++ b/timeutils/json_test.go
@@ -0,0 +1,47 @@
+package timeutils
+
+import (
+	"testing"
+	"time"
+)
+
+// Testing to ensure 'year' fields is between 0 and 9999
+func TestFastMarshalJSONWithInvalidDate(t *testing.T) {
+	aTime := time.Date(-1, 1, 1, 0, 0, 0, 0, time.Local)
+	json, err := FastMarshalJSON(aTime)
+	if err == nil {
+		t.Fatalf("FastMarshalJSON should throw an error, but was '%v'", json)
+	}
+	anotherTime := time.Date(10000, 1, 1, 0, 0, 0, 0, time.Local)
+	json, err = FastMarshalJSON(anotherTime)
+	if err == nil {
+		t.Fatalf("FastMarshalJSON should throw an error, but was '%v'", json)
+	}
+
+}
+
+func TestFastMarshalJSON(t *testing.T) {
+	aTime := time.Date(2015, 5, 29, 11, 1, 2, 3, time.UTC)
+	json, err := FastMarshalJSON(aTime)
+	if err != nil {
+		t.Fatal(err)
+	}
+	expected := "\"2015-05-29T11:01:02.000000003Z\""
+	if json != expected {
+		t.Fatalf("Expected %v, got %v", expected, json)
+	}
+
+	location, err := time.LoadLocation("Europe/Paris")
+	if err != nil {
+		t.Fatal(err)
+	}
+	aTime = time.Date(2015, 5, 29, 11, 1, 2, 3, location)
+	json, err = FastMarshalJSON(aTime)
+	if err != nil {
+		t.Fatal(err)
+	}
+	expected = "\"2015-05-29T11:01:02.000000003+02:00\""
+	if json != expected {
+		t.Fatalf("Expected %v, got %v", expected, json)
+	}
+}