feat(adapter): define Adapter interface and FileSet

internal/adapter/adapter_test.go

@@ -0,0 +1,25 @@
+package adapter
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestFileSetAddAndIterate(t *testing.T) {
+	fs := NewFileSet()
+	fs.Add(File{Dest: "/tmp/a", Kind: RenderedFile, Content: []byte("a")})
+	fs.Add(File{Dest: "/tmp/b", Kind: SymlinkFile, SymlinkTarget: "/canon/b"})
+
+	seen := map[string]Kind{}
+	fs.ForEach(func(f File) {
+		seen[f.Dest] = f.Kind
+	})
+	assert.Equal(t, RenderedFile, seen["/tmp/a"])
+	assert.Equal(t, SymlinkFile, seen["/tmp/b"])
+}
+
+func TestKindString(t *testing.T) {
+	assert.Equal(t, "rendered", RenderedFile.String())
+	assert.Equal(t, "symlink-file", SymlinkFile.String())
+}