refactor: better project structure (#35)

This project is starting to grow, and I've seen flaws in the initial
project structure design
I think I'll restructure the entire project directory for better
scalability and also cleaner

spec/utils_test.go

@@ -0,0 +1,53 @@
+package spec
+
+import (
+	"reflect"
+	"testing"
+)
+
+func TestTokenize(t *testing.T) {
+	tests := []struct {
+		name     string
+		input    string
+		expected []string
+	}{
+		{"Empty input", "", []string{""}},
+		{"Trailing space", "git ", []string{"git", ""}},
+		{"Multi-space", "git  add", []string{"git", "add"}},
+		{"Quoted string", "git commit -m \"hello world\"", []string{"git", "commit", "-m", "hello world"}},
+		{"Quote not closed", "git commit -m \"hello", []string{"git", "commit", "-m", "hello"}},
+		{"Single quote", "git commit -m 'hello world'", []string{"git", "commit", "-m", "hello world"}},
+		{"Backslash escape", "git commit -m \"hello\\ world\"", []string{"git", "commit", "-m", "hello world"}},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := Tokenize(tt.input)
+			if !reflect.DeepEqual(got, tt.expected) {
+				t.Errorf("Tokenize(%q) = %v; want %v", tt.input, got, tt.expected)
+			}
+		})
+	}
+}
+
+func TestHasPrefix(t *testing.T) {
+	tests := []struct {
+		name   string
+		s      string
+		prefix string
+		want   bool
+	}{
+		{"Case insensitive", "Hello", "hel", true},
+		{"Unicode support", "Thử nghiệm", "thử", true},
+		{"Prefix longer", "Iris", "Iris-Longer", false},
+		{"Empty prefix", "Iris", "", true},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := HasPrefix(tt.s, tt.prefix); got != tt.want {
+				t.Errorf("HasPrefix(%q, %q) = %v; want %v", tt.s, tt.prefix, got, tt.want)
+			}
+		})
+	}
+}