chore: update instance type for better type safety (#412)

use 0 value as unknown to force intentional use of type

pkg/instance/type.go

@@ -5,15 +5,24 @@ type InstanceType int
 
 // Possible types of the instance
 const (
-	BasicInstance InstanceType = iota
+	UnknownInstance InstanceType = iota
+	BasicInstance
 	ExecutorInstance
 	TimeoutHandlerInstance
 )
 
 // String returns the string representation of the type
 func (s InstanceType) String() string {
-	if s < 0 || s > 2 {
-		return "Unknown"
+	switch s {
+	case BasicInstance:
+		return "BasicInstance"
+	case ExecutorInstance:
+		return "ExecutorInstance"
+	case TimeoutHandlerInstance:
+		return "TimeoutHandlerInstance"
+	case UnknownInstance:
+	default:
 	}
-	return [...]string{"BasicInstance", "ExecutorInstance", "TimeoutHandlerInstance"}[s]
+	return "Unknown"
+
 }

pkg/instance/type_test.go

@@ -0,0 +1,49 @@
+package instance
+
+import (
+	"testing"
+)
+
+func TestInstanceType(t *testing.T) {
+	t.Parallel()
+	tests := []struct {
+		name string
+		in   InstanceType
+		want string
+	}{
+		{
+			name: "BasicInstance", // Test case name
+			in:   BasicInstance,   // Input
+			want: "BasicInstance", // Expected output
+		},
+		{
+			name: "ExecutorInstance",
+			in:   ExecutorInstance,
+			want: "ExecutorInstance",
+		},
+		{
+			name: "TimeoutHandlerInstance",
+			in:   TimeoutHandlerInstance,
+			want: "TimeoutHandlerInstance",
+		},
+		{
+			name: "UnknownInstance",
+			in:   UnknownInstance,
+			want: "Unknown",
+		},
+		{
+			name: "4",
+			in:   4,
+			want: "Unknown",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := tt.in.String()
+			if got != tt.want {
+				t.Errorf("got %q; want %q", got, tt.want)
+			}
+		})
+	}
+}