From 75446032b914bb0be5e07da29c976034c0a666cf Mon Sep 17 00:00:00 2001
From: Torkel Rogstad <torkel@rogstad.io>
Date: Fri, 12 Mar 2021 14:42:51 +0100
Subject: [PATCH] Normalize UTC timestamps to comply with stdlib

---
 timestamptz.go      | 22 ++++++++++++++++++++--
 timestamptz_test.go |  6 ++----
 2 files changed, 22 insertions(+), 6 deletions(-)

diff --git a/timestamptz.go b/timestamptz.go
index 299a866..5870197 100644
--- a/timestamptz.go
+++ b/timestamptz.go
@@ -124,7 +124,7 @@ func (dst *Timestamptz) DecodeText(ci *ConnInfo, src []byte) error {
 			return err
 		}
 
-		*dst = Timestamptz{Time: tim, Status: Present}
+		*dst = Timestamptz{Time: normalizePotentialUTC(tim), Status: Present}
 	}
 
 	return nil
@@ -231,6 +231,9 @@ func (src Timestamptz) Value() (driver.Value, error) {
 		if src.InfinityModifier != None {
 			return src.InfinityModifier.String(), nil
 		}
+		if src.Time.Location().String() == time.UTC.String() {
+			return src.Time.UTC(), nil
+		}
 		return src.Time, nil
 	case Null:
 		return nil, nil
@@ -289,8 +292,23 @@ func (dst *Timestamptz) UnmarshalJSON(b []byte) error {
 			return err
 		}
 
-		*dst = Timestamptz{Time: tim, Status: Present}
+		*dst = Timestamptz{Time: normalizePotentialUTC(tim), Status: Present}
 	}
 
 	return nil
 }
+
+// Normalize timestamps in UTC location to behave similarly to how the Golang
+// standard library does it: UTC timestamps lack a .loc value.
+//
+// Reason for this: when comparing two timestamps with reflect.DeepEqual (generally
+// speaking not a good idea, but several testing libraries (for example testify)
+// does this), their location data needs to be equal for them to be considered
+// equal.
+func normalizePotentialUTC(timestamp time.Time) time.Time {
+	if timestamp.Location().String() != time.UTC.String() {
+		return timestamp
+	}
+
+	return timestamp.UTC()
+}
diff --git a/timestamptz_test.go b/timestamptz_test.go
index c3f6396..2ff326b 100644
--- a/timestamptz_test.go
+++ b/timestamptz_test.go
@@ -70,8 +70,7 @@ func TestTimestamptzNanosecondsTruncated(t *testing.T) {
 				t.Errorf("%d. EncodeText failed - %v", i, err)
 			}
 
-			tstz.DecodeText(nil, buf)
-			if err != nil {
+			if err := tstz.DecodeText(nil, buf); err != nil {
 				t.Errorf("%d. DecodeText failed - %v", i, err)
 			}
 
@@ -87,8 +86,7 @@ func TestTimestamptzNanosecondsTruncated(t *testing.T) {
 				t.Errorf("%d. EncodeBinary failed - %v", i, err)
 			}
 
-			tstz.DecodeBinary(nil, buf)
-			if err != nil {
+			if err := tstz.DecodeBinary(nil, buf); err != nil {
 				t.Errorf("%d. DecodeBinary failed - %v", i, err)
 			}