Handle default values for fixed types properly

schema/fixed.go

@@ -122,7 +122,7 @@ func (s *FixedDefinition) DefaultValue(lvalue string, rvalue interface{}) (strin
 		return "", fmt.Errorf("Expected string as default for field %v, got %q", lvalue, rvalue)
 	}
 
-	return fmt.Sprintf("%v = []byte(%q)", lvalue, rvalue), nil
+	return fmt.Sprintf("copy(%v[:], []byte(%q))", lvalue, rvalue), nil
 }
 
 func (s *FixedDefinition) IsReadableBy(d Definition) bool {

test/default-fixed/fixed-default.avsc

@@ -0,0 +1,15 @@
+{
+    "type": "record",
+    "name": "FixedDefaultTestRecord",
+    "fields": [
+        {
+            "name": "FixedField",
+            "type": {
+                "name": "TestFixedDefaultType",
+                "size": 12,
+                "type": "fixed"
+            },
+            "default": "\u0000\u0001\u0012\u0000\u0013\u0043\u0000\u0001\u0012\u0000\u0013\u0053"
+        }
+    ]
+}

test/default-fixed/generate.go

@@ -0,0 +1,3 @@
+package avro
+
+//go:generate $GOPATH/bin/gogen-avro . fixed-default.avsc

test/default-fixed/schema_test.go

@@ -0,0 +1,17 @@
+package avro
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestDefault(t *testing.T) {
+	var fixedDefault = NewFixedDefaultTestRecord()
+	fixedDefault.SetDefault(0)
+
+	expected := FixedDefaultTestRecord{
+		FixedField: [12]byte{0, 1, 18, 0, 19, 67, 0, 1, 18, 0, 19, 83},
+	}
+	assert.Equal(t, &expected, fixedDefault, "Comparing default value")
+}