feat(platform): add PackageManager interface and Pacman implementation

internal/platform/pacman_test.go

@@ -0,0 +1,87 @@
+package platform
+
+import (
+	"context"
+	"errors"
+	"reflect"
+	"testing"
+)
+
+type fakeRunner struct {
+	runCalls    [][]string
+	outputCalls [][]string
+	outputErr   error
+	output      []byte
+}
+
+func (f *fakeRunner) Run(_ context.Context, name string, args ...string) error {
+	f.runCalls = append(f.runCalls, append([]string{name}, args...))
+	return nil
+}
+
+func (f *fakeRunner) Output(_ context.Context, name string, args ...string) ([]byte, error) {
+	f.outputCalls = append(f.outputCalls, append([]string{name}, args...))
+	return f.output, f.outputErr
+}
+
+func TestPacmanInstallShellsOutCorrectly(t *testing.T) {
+	r := &fakeRunner{}
+	p := NewPacman(r)
+	if err := p.Install(context.Background(), []string{"tio", "git"}); err != nil {
+		t.Fatal(err)
+	}
+	if len(r.runCalls) != 1 {
+		t.Fatalf("run calls = %d", len(r.runCalls))
+	}
+	want := []string{"sudo", "pacman", "-S", "--needed", "--noconfirm", "tio", "git"}
+	if !reflect.DeepEqual(r.runCalls[0], want) {
+		t.Fatalf("args = %v, want %v", r.runCalls[0], want)
+	}
+}
+
+func TestPacmanInstallEmptyIsNoop(t *testing.T) {
+	r := &fakeRunner{}
+	p := NewPacman(r)
+	if err := p.Install(context.Background(), nil); err != nil {
+		t.Fatal(err)
+	}
+	if len(r.runCalls) != 0 {
+		t.Fatalf("expected no calls, got %v", r.runCalls)
+	}
+}
+
+func TestPacmanIsInstalledTrue(t *testing.T) {
+	r := &fakeRunner{output: []byte("tio 3.2-1")}
+	p := NewPacman(r)
+	ok, err := p.IsInstalled(context.Background(), "tio")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !ok {
+		t.Fatal("want installed=true")
+	}
+}
+
+func TestPacmanIsInstalledFalseOnError(t *testing.T) {
+	r := &fakeRunner{outputErr: errors.New("not found")}
+	p := NewPacman(r)
+	ok, err := p.IsInstalled(context.Background(), "ghost")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if ok {
+		t.Fatal("want installed=false")
+	}
+}
+
+func TestPacmanUpdate(t *testing.T) {
+	r := &fakeRunner{}
+	p := NewPacman(r)
+	if err := p.Update(context.Background()); err != nil {
+		t.Fatal(err)
+	}
+	want := []string{"sudo", "pacman", "-Sy"}
+	if !reflect.DeepEqual(r.runCalls[0], want) {
+		t.Fatalf("args = %v, want %v", r.runCalls[0], want)
+	}
+}