1 files changed, 104 insertions, 0 deletions
diff --git a/src/cmd/go/internal/modindex/index_test.go b/src/cmd/go/internal/modindex/index_test.go
new file mode 100644
index 0000000..6bc62f3
--- /dev/null
+++ b/src/cmd/go/internal/modindex/index_test.go
@@ -0,0 +1,104 @@
+// Copyright 2022 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package modindex
+
+import (
+	"encoding/hex"
+	"encoding/json"
+	"go/build"
+	"internal/diff"
+	"path/filepath"
+	"reflect"
+	"runtime"
+	"testing"
+)
+
+func init() {
+	isTest = true
+	enabled = true // to allow GODEBUG=goindex=0 go test, when things are very broken
+}
+
+func TestIndex(t *testing.T) {
+	src := filepath.Join(runtime.GOROOT(), "src")
+	checkPkg := func(t *testing.T, m *Module, pkg string, data []byte) {
+		p := m.Package(pkg)
+		bp, err := p.Import(build.Default, build.ImportComment)
+		if err != nil {
+			t.Fatal(err)
+		}
+		bp1, err := build.Default.Import(".", filepath.Join(src, pkg), build.ImportComment)
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		if !reflect.DeepEqual(bp, bp1) {
+			t.Errorf("mismatch")
+			t.Logf("index:\n%s", hex.Dump(data))
+
+			js, err := json.MarshalIndent(bp, "", "\t")
+			if err != nil {
+				t.Fatal(err)
+			}
+			js1, err := json.MarshalIndent(bp1, "", "\t")
+			if err != nil {
+				t.Fatal(err)
+			}
+			t.Logf("diff:\n%s", diff.Diff("index", js, "correct", js1))
+			t.FailNow()
+		}
+	}
+
+	// Check packages in increasing complexity, one at a time.
+	pkgs := []string{
+		"crypto",
+		"encoding",
+		"unsafe",
+		"encoding/json",
+		"runtime",
+		"net",
+	}
+	var raws []*rawPackage
+	for _, pkg := range pkgs {
+		raw := importRaw(src, pkg)
+		raws = append(raws, raw)
+		t.Run(pkg, func(t *testing.T) {
+			data := encodeModuleBytes([]*rawPackage{raw})
+			m, err := fromBytes(src, data)
+			if err != nil {
+				t.Fatal(err)
+			}
+			checkPkg(t, m, pkg, data)
+		})
+	}
+
+	// Check that a multi-package index works too.
+	t.Run("all", func(t *testing.T) {
+		data := encodeModuleBytes(raws)
+		m, err := fromBytes(src, data)
+		if err != nil {
+			t.Fatal(err)
+		}
+		for _, pkg := range pkgs {
+			checkPkg(t, m, pkg, data)
+		}
+	})
+}
+
+func TestImportRaw_IgnoreNonGo(t *testing.T) {
+	path := filepath.Join("testdata", "ignore_non_source")
+	p := importRaw(path, ".")
+
+	wantFiles := []string{"a.syso", "b.go", "c.c"}
+
+	var gotFiles []string
+	for i := range p.sourceFiles {
+		gotFiles = append(gotFiles, p.sourceFiles[i].name)
+	}
+
+	if !reflect.DeepEqual(gotFiles, wantFiles) {
+		t.Errorf("names of files in importRaw(testdata/ignore_non_source): got %v; want %v",
+			gotFiles, wantFiles)
+	}
+}