add Block + Component, add TextComponent with min, max and regex validators and early NumberComponent

internal/block/validation/required_test.go

@@ -0,0 +1,35 @@
+package validation
+
+import (
+	"testing"
+)
+
+func TestRequired(t *testing.T) {
+	cfg := &ComponentConfig{}
+	Required()(cfg)
+
+	if len(cfg.Validators) != 1 {
+		t.Fatalf("expect 1 validator, got %d", len(cfg.Validators))
+	}
+
+	validate := cfg.Validators[0]
+
+	tests := []struct {
+		name    string
+		value   any
+		wantErr bool
+	}{
+		{"nil value", nil, true},
+		{"empty string", "", true},
+		{"non-empty string", "hello", false},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			err := validate(tt.value)
+			if (err != nil) != tt.wantErr {
+				t.Errorf("validate(%v) error = %v, wantErr %v", tt.value, err, tt.wantErr)
+			}
+		})
+	}
+}