feat(01-01): generate and build hello app from manifest

- Add summer build with validated summer.yaml codegen
- Generate stable main.go and plugins.gen.go then go build
- Smoke-test the built hello binary greeter:hello command

internal/build/build_test.go

@@ -0,0 +1,129 @@
+package build
+
+import (
+	"bytes"
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+)
+
+func TestLoadHelloManifest(t *testing.T) {
+	m, err := LoadManifest(filepath.Join("..", "..", "examples", "hello", "summer.yaml"))
+	if err != nil {
+		t.Fatal(err)
+	}
+	if m.Binary != "hello" {
+		t.Fatalf("binary = %q", m.Binary)
+	}
+	if len(m.Plugins) != 2 || m.Plugins[0].ID != "golem15.hello" || m.Plugins[1].ID != "golem15.greeter" {
+		t.Fatalf("plugins = %+v", m.Plugins)
+	}
+}
+
+func TestParseManifestRejectsDuplicatesAndInvalidPaths(t *testing.T) {
+	dir := t.TempDir()
+
+	t.Run("duplicate id", func(t *testing.T) {
+		path := filepath.Join(dir, "dup.yaml")
+		write(t, path, "module: example.com/app\nbinary: app\nplugins:\n  - id: a.b\n    module: example.com/one\n  - id: a.b\n    module: example.com/two\n")
+		if _, err := LoadManifest(path); err == nil || !strings.Contains(err.Error(), "a.b") {
+			t.Fatalf("want duplicate id error, got %v", err)
+		}
+	})
+
+	t.Run("invalid module", func(t *testing.T) {
+		path := filepath.Join(dir, "bad.yaml")
+		write(t, path, "module: example.com/app\nbinary: app\nplugins:\n  - id: a.b\n    module: \"example.com/one; rm -rf /\"\n")
+		if _, err := LoadManifest(path); err == nil {
+			t.Fatal("want invalid module error")
+		}
+	})
+
+	t.Run("path traversal module", func(t *testing.T) {
+		path := filepath.Join(dir, "dotdot.yaml")
+		write(t, path, "module: example.com/app\nbinary: app\nplugins:\n  - id: a.b\n    module: example.com/../evil\n")
+		if _, err := LoadManifest(path); err == nil {
+			t.Fatal("want invalid module error")
+		}
+	})
+}
+
+func TestGenerateStableQuotedImportsInManifestOrder(t *testing.T) {
+	m := Manifest{
+		Module: "example.com/app",
+		Binary: "hello",
+		Plugins: []Plugin{
+			{ID: "golem15.hello", Module: "example.com/app/plugins/base"},
+			{ID: "golem15.greeter", Module: "example.com/app/plugins/greeter"},
+		},
+	}
+	first, err := generatePluginsGen(m)
+	if err != nil {
+		t.Fatal(err)
+	}
+	second, err := generatePluginsGen(m)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !bytes.Equal(first, second) {
+		t.Fatal("generated plugins.gen.go is not byte-stable")
+	}
+	src := string(first)
+	baseAt := strings.Index(src, `example.com/app/plugins/base`)
+	greeterAt := strings.Index(src, `example.com/app/plugins/greeter`)
+	if baseAt < 0 || greeterAt < 0 || baseAt > greeterAt {
+		t.Fatalf("imports not in manifest order:\n%s", src)
+	}
+	if !strings.Contains(src, "\t_ \"example.com/app/plugins/base\"") {
+		t.Fatalf("import is not Go-quoted:\n%s", src)
+	}
+
+	mainSrc, err := generateMain(m)
+	if err != nil {
+		t.Fatal(err)
+	}
+	again, err := generateMain(m)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !bytes.Equal(mainSrc, again) {
+		t.Fatal("generated main.go is not byte-stable")
+	}
+	if !bytes.Contains(mainSrc, []byte(`bonfire.NewRoot("hello"`)) {
+		t.Fatalf("main does not use manifest binary:\n%s", mainSrc)
+	}
+	if bytes.Contains(mainSrc, []byte("examples/hello")) {
+		t.Fatal("generated main hard-codes examples/hello")
+	}
+}
+
+func TestWriteIfChangedSkipsIdenticalBytes(t *testing.T) {
+	dir := t.TempDir()
+	path := filepath.Join(dir, "out.go")
+	content := []byte("package main\n")
+	if err := writeIfChanged(path, content); err != nil {
+		t.Fatal(err)
+	}
+	info, err := os.Stat(path)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if err := writeIfChanged(path, content); err != nil {
+		t.Fatal(err)
+	}
+	again, err := os.Stat(path)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !info.ModTime().Equal(again.ModTime()) {
+		t.Fatal("identical content rewrote the file")
+	}
+}
+
+func write(t *testing.T, path, body string) {
+	t.Helper()
+	if err := os.WriteFile(path, []byte(body), 0o644); err != nil {
+		t.Fatal(err)
+	}
+}