diff --git a/postgres/numeric/numeric_test.go b/postgres/numeric/numeric_test.go
index b7ef5e9..9e89a38 100644
--- a/postgres/numeric/numeric_test.go
+++ b/postgres/numeric/numeric_test.go
@@ -17,6 +17,15 @@ func TestMarshalJSON(t *testing.T) {
 		{numeric.Zero(), `0`},
 		{numeric.MustParse("1.23"), "1.23"},
 		{numeric.MustParse("1,24"), "1.24"},
+		{numeric.MustParse("1"), "1"},
+		{numeric.MustParse("10"), "10"},
+		{numeric.MustParse("100"), "100"},
+		{numeric.MustParse("1000"), "1000"},
+		{numeric.MustParse("0.1"), "0.1"},
+		{numeric.MustParse("0.01"), "0.01"},
+		{numeric.MustParse("0.001"), "0.001"},
+		{numeric.MustParse("0.0001"), "0.0001"},
+		{numeric.MustParse("123456789.12345"), "123456789.12345"},
 		{numeric.MustParse("123456789.12345"), "123456789.12345"},
 		{numeric.MustParse("-1.23"), "-1.23"},
 		{numeric.MustParse("-1,24"), "-1.24"},
@@ -53,6 +62,11 @@ func TestParse(t *testing.T) {
 		{numeric.FromInt64WithExp(1, 0), `1`},
 		{numeric.FromInt64WithExp(1, 1), `10`},
 		{numeric.FromInt64WithExp(1, 2), `100`},
+		{numeric.FromInt64WithExp(1, 3), `1000`},
+		{numeric.FromInt64WithExp(1, -1), `0.1`},
+		{numeric.FromInt64WithExp(1, -2), `0.01`},
+		{numeric.FromInt64WithExp(1, -3), `0.001`},
+		{numeric.FromInt64WithExp(1, -4), `0.0001`},
 		{numeric.FromInt64WithExp(123, -2), "1.23"},
 		{numeric.FromInt64WithExp(124, -2), "1,24"},
 		{numeric.FromInt64WithExp(12345678912345, -5), "123456789.12345"},