Append query options to context instead of overwriting. (#860)

* Append query options to context instead of overwriting.

* lint.

* Address feedback.

* Use asserts.

context.go

@@ -132,9 +132,7 @@ func WithStdAsync(wait bool) QueryOption {
 }
 
 func Context(parent context.Context, options ...QueryOption) context.Context {
-	opt := QueryOptions{
-		settings: make(Settings),
-	}
+	opt := queryOptions(parent)
 	for _, f := range options {
 		f(&opt)
 	}

context_test.go

@@ -0,0 +1,35 @@
+package clickhouse
+
+import (
+	"context"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestContext(t *testing.T) {
+	t.Run("call context multiple times making sure query options are persisted across calls",
+		func(t *testing.T) {
+			ctx := Context(context.Background(), WithQueryID("a"))
+			ctx = Context(ctx, WithQuotaKey("b"))
+			ctx = Context(ctx, WithSettings(Settings{
+				"c": "d",
+			}))
+
+			opts := queryOptions(ctx)
+			assert.Equal(t, "a", opts.queryID)
+			assert.Equal(t, "b", opts.quotaKey)
+			assert.Equal(t, "d", opts.settings["c"])
+		},
+	)
+
+	t.Run("call context multiple times making sure query options are persisted across calls",
+		func(t *testing.T) {
+			ctx := Context(context.Background(), WithQueryID("a"))
+			ctx = Context(ctx, WithQueryID("b"))
+
+			opts := queryOptions(ctx)
+			assert.Equal(t, "b", opts.queryID)
+		},
+	)
+}