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/lookup_test.go

@@ -0,0 +1,93 @@
+package spec
+
+import (
+	"strings"
+	"sync"
+	"testing"
+)
+
+func TestLookup(t *testing.T) {
+	// Setup Registry
+	Registry = make(map[string]*Spec)
+	Register(&Spec{
+		Name: "git",
+		Subcommands: []Subcommand{
+			{Name: "commit", Options: []Option{{Name: "--message"}}, MaxArgs: 1},
+			{Name: "remote", Subcommands: []Subcommand{{Name: "add"}}},
+		},
+		Options: []Option{{Name: "--verbose"}},
+	})
+
+	// Setup Aliases
+	ShellAliases = map[string]string{
+		"gca": "git commit -a",
+		"ta":  "tmux a -t",
+	}
+
+	tests := []struct {
+		name        string
+		input       string
+		minResults  int
+		mustContain string
+	}{
+		{"Top-level", "gi", 1, "git"},
+		{"Subcommand", "git ", 1, "git commit"},
+		{"Alias expansion", "gca", 1, "git commit -a"},
+		{"Alias with space", "ta", 1, "tmux a -t"},
+		{"Deep subcommand", "git remote ", 1, "git remote add"},
+		{"Option dedup", "git --verbose -", 0, ""},
+		{"Flag with value ignore", "git --output=json ", 2, "git --output=json commit"},
+		{"Unknown root command", "unknowncmd ", 0, ""},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			results := Lookup(tt.input)
+			if len(results) < tt.minResults {
+				t.Errorf("Lookup(%q) got %d results; want at least %d", tt.input, len(results), tt.minResults)
+			}
+			if tt.mustContain != "" {
+				found := false
+				for _, r := range results {
+					if strings.Contains(r.Cmd, tt.mustContain) || strings.Contains(r.Desc, tt.mustContain) {
+						found = true
+						break
+					}
+				}
+				if !found {
+					t.Errorf("Lookup(%q) results did not contain %q", tt.input, tt.mustContain)
+				}
+			}
+		})
+	}
+}
+
+func TestLookupConcurrent(t *testing.T) {
+	Registry = make(map[string]*Spec)
+	Register(&Spec{
+		Name: "git",
+		Subcommands: []Subcommand{
+			{Name: "commit", Options: []Option{{Name: "--message"}}, MaxArgs: 1},
+		},
+	})
+
+	ShellAliases = map[string]string{
+		"gca": "git commit -a",
+	}
+
+	var wg sync.WaitGroup
+	const goroutines = 10
+	const iterations = 50
+
+	for range goroutines {
+		wg.Add(1)
+		go func() {
+			defer wg.Done()
+			for range iterations {
+				_ = Lookup("gca")
+				_ = Lookup("git ")
+			}
+		}()
+	}
+	wg.Wait()
+}