fixing auto-completion

main_test.go

@@ -5,6 +5,8 @@ import (
 	"os"
 	"os/exec"
 	"path/filepath"
+	"reflect"
+	"sort"
 	"strings"
 	"testing"
 
@@ -781,3 +783,68 @@ func TestFilePathCompleter_NoMatches(t *testing.T) {
 		t.Errorf("expected no matches for non-existent prefix, got: %v", matches)
 	}
 }
+
+// completeLine runs the completer on line (cursor at the end) and returns the
+// candidates as strings together with the reported length.
+func completeLine(line string) ([]string, int) {
+	cands, length := newShellCompleter().Do([]rune(line), len([]rune(line)))
+	var out []string
+	for _, c := range cands {
+		out = append(out, string(c))
+	}
+	sort.Strings(out)
+	return out, length
+}
+
+func TestShellCompleter_Do(t *testing.T) {
+	origDir, _ := os.Getwd()
+	defer os.Chdir(origDir)
+
+	tmpDir := t.TempDir()
+	os.Chdir(tmpDir)
+	os.Create("main.go")
+	os.Create("my file.txt")
+	os.Create(".hidden")
+	os.Mkdir("subdir", 0755)
+	os.Create("subdir/inner.txt")
+
+	// Controlled PATH with one executable, one non-executable and a
+	// duplicate of a builtin
+	binDir := t.TempDir()
+	os.WriteFile(filepath.Join(binDir, "gitty"), nil, 0755)
+	os.WriteFile(filepath.Join(binDir, "girl"), nil, 0644)
+	os.WriteFile(filepath.Join(binDir, "echo"), nil, 0755)
+	os.Mkdir(filepath.Join(binDir, "gidir"), 0755)
+	t.Setenv("PATH", binDir)
+
+	tests := []struct {
+		line   string
+		want   []string
+		length int
+	}{
+		{"c", []string{"d "}, 1},
+		{"e", []string{"cho ", "xit ", "xport "}, 1},
+		{"gi", []string{"tty "}, 2},
+		{"  gi", []string{"tty "}, 2},
+		{"ls gi", nil, 2},
+		{"ls ma", []string{"in.go"}, 2},
+		{"ls su", []string{"bdir/"}, 2},
+		{"ls subdir/", []string{"inner.txt"}, 0},
+		{"ls subdir/in", []string{"ner.txt"}, 2},
+		{"ls my", []string{`\ file.txt`}, 2},
+		{`ls my\ f`, []string{"ile.txt"}, 4},
+		{`ls "my f`, []string{"ile.txt"}, 4},
+		{"ls ./ma", []string{"in.go"}, 2},
+		{"ls .h", []string{"idden"}, 2},
+		{"ls ", []string{"main.go", `my\ file.txt`, "subdir/"}, 0},
+		{"ls " + tmpDir + "/ma", []string{"in.go"}, 2},
+		{"ls xyz", nil, 3},
+		{"ls ~", []string{"/"}, 1},
+	}
+	for _, tt := range tests {
+		got, length := completeLine(tt.line)
+		if !reflect.DeepEqual(got, tt.want) || length != tt.length {
+			t.Errorf("Do(%q) = %q, %d; want %q, %d", tt.line, got, length, tt.want, tt.length)
+		}
+	}
+}