Support scanning uint64 (shopspring#364)

Author: serprex

decimal.go

@@ -1847,6 +1847,11 @@ func (d *Decimal) Scan(value interface{}) error {
 		*d = New(v, 0)
 		return nil
 
+	case uint64:
+		// while clickhouse may send 0 in db as uint64
+		*d = NewFromUint64(v)
+		return nil
+
 	default:
 		// default is trying to interpret value stored as string
 		str, err := unquoteIfQuoted(v)

decimal_test.go

@@ -2416,104 +2416,57 @@ func TestDecimal_Max(t *testing.T) {
 	}
 }
 
-func TestDecimal_Scan(t *testing.T) {
-	// test the Scan method that implements the
-	// sql.Scanner interface
-	// check for the for different type of values
-	// that are possible to be received from the database
-	// drivers
+func scanHelper(t *testing.T, dbval interface{}, expected Decimal) {
+	t.Helper()
 
-	// in normal operations the db driver (sqlite at least)
-	// will return an int64 if you specified a numeric format
 	a := Decimal{}
-	dbvalue := 54.33
-	expected := NewFromFloat(dbvalue)
-
-	err := a.Scan(dbvalue)
-	if err != nil {
+	if err := a.Scan(dbval); err != nil {
 		// Scan failed... no need to test result value
-		t.Errorf("a.Scan(54.33) failed with message: %s", err)
-
-	} else {
+		t.Errorf("a.Scan(%v) failed with message: %s", dbval, err)
+	} else if !a.Equal(expected) {
 		// Scan succeeded... test resulting values
-		if !a.Equal(expected) {
-			t.Errorf("%s does not equal to %s", a, expected)
-		}
+		t.Errorf("%s does not equal to %s", a, expected)
 	}
+}
+
+func TestDecimal_Scan(t *testing.T) {
+	// test the Scan method that implements the sql.Scanner interface
+	// check different types received from various database drivers
+
+	dbvalue := 54.33
+	expected := NewFromFloat(dbvalue)
+	scanHelper(t, dbvalue, expected)
 
 	// apparently MySQL 5.7.16 and returns these as float32 so we need
 	// to handle these as well
 	dbvalueFloat32 := float32(54.33)
 	expected = NewFromFloat(float64(dbvalueFloat32))
-
-	err = a.Scan(dbvalueFloat32)
-	if err != nil {
-		// Scan failed... no need to test result value
-		t.Errorf("a.Scan(54.33) failed with message: %s", err)
-
-	} else {
-		// Scan succeeded... test resulting values
-		if !a.Equal(expected) {
-			t.Errorf("%s does not equal to %s", a, expected)
-		}
-	}
+	scanHelper(t, dbvalueFloat32, expected)
 
 	// at least SQLite returns an int64 when 0 is stored in the db
 	// and you specified a numeric format on the schema
 	dbvalueInt := int64(0)
 	expected = New(dbvalueInt, 0)
+	scanHelper(t, dbvalueInt, expected)
 
-	err = a.Scan(dbvalueInt)
-	if err != nil {
-		// Scan failed... no need to test result value
-		t.Errorf("a.Scan(0) failed with message: %s", err)
-
-	} else {
-		// Scan succeeded... test resulting values
-		if !a.Equal(expected) {
-			t.Errorf("%s does not equal to %s", a, expected)
-		}
-	}
+	// also test uint64
+	dbvalueUint64 := uint64(2)
+	expected = New(2, 0)
+	scanHelper(t, dbvalueUint64, expected)
 
 	// in case you specified a varchar in your SQL schema,
-	// the database driver will return byte slice []byte
+	// the database driver may return either []byte or string
 	valueStr := "535.666"
 	dbvalueStr := []byte(valueStr)
-	expected, err = NewFromString(valueStr)
-	if err != nil {
-		t.Fatal(err)
-	}
-
-	err = a.Scan(dbvalueStr)
-	if err != nil {
-		// Scan failed... no need to test result value
-		t.Errorf("a.Scan('535.666') failed with message: %s", err)
-
-	} else {
-		// Scan succeeded... test resulting values
-		if !a.Equal(expected) {
-			t.Errorf("%s does not equal to %s", a, expected)
-		}
-	}
-
-	// lib/pq can also return strings
-	expected, err = NewFromString(valueStr)
+	expected, err := NewFromString(valueStr)
 	if err != nil {
 		t.Fatal(err)
 	}
-
-	err = a.Scan(valueStr)
-	if err != nil {
-		// Scan failed... no need to test result value
-		t.Errorf("a.Scan('535.666') failed with message: %s", err)
-	} else {
-		// Scan succeeded... test resulting values
-		if !a.Equal(expected) {
-			t.Errorf("%s does not equal to %s", a, expected)
-		}
-	}
+	scanHelper(t, dbvalueStr, expected)
+	scanHelper(t, valueStr, expected)
 
 	type foo struct{}
+	a := Decimal{}
 	err = a.Scan(foo{})
 	if err == nil {
 		t.Errorf("a.Scan(Foo{}) should have thrown an error but did not")