diff --git a/itests/config/config.go b/itests/config/config.go
index dea1ad76ee..23d797caaa 100644
--- a/itests/config/config.go
+++ b/itests/config/config.go
@@ -138,9 +138,11 @@ func (c *ScalaConfigurator) DockerRunOptions() *dockertest.RunOptions {
 		c.imageTag = DefaultImageTag
 	}
 
-	var kps strings.Builder
+	kps := new(strings.Builder)
 	for i, kp := range c.knownPeers {
-		kps.WriteString(fmt.Sprintf("-Dwaves.network.known-peers.%d=%s:%s ", i, kp, BindPort))
+		if _, err := fmt.Fprintf(kps, "-Dwaves.network.known-peers.%d=%s:%s ", i, kp, BindPort); err != nil {
+			panic(err)
+		}
 	}
 	opt := &dockertest.RunOptions{
 		Repository: c.imageRepository,
diff --git a/pkg/ride/compiler/parser_test.go b/pkg/ride/compiler/parser_test.go
index 006db6435a..c96b6f85f5 100644
--- a/pkg/ride/compiler/parser_test.go
+++ b/pkg/ride/compiler/parser_test.go
@@ -492,9 +492,10 @@ Type #comment
 }
 
 func TestHugeScript(t *testing.T) {
-	sb := strings.Builder{}
+	sb := new(strings.Builder)
 	for i := range 10000 {
-		sb.WriteString(fmt.Sprintf("let i%d = true\n", i))
+		_, err := fmt.Fprintf(sb, "let i%d = true\n", i)
+		require.Nil(t, err)
 	}
 	sb.WriteString("i9999\n")
 	ast, _, err := buildAST(t, sb.String(), false)