diff --git a/context/context_test.go b/context/context_test.go
index 8f11aa2..943b984 100644
--- a/context/context_test.go
+++ b/context/context_test.go
@@ -431,6 +431,51 @@ func TestNoDep(t *testing.T) {
 	verifyChecksum(g, c, "new")
 }
 
+func TestMainTest(t *testing.T) {
+	g := gt.New(t)
+	defer g.Clean()
+
+	// This test relies on the file list being sorted. Normally not required.
+	testNeedsSortOrder = true
+
+	g.Setup("co1/pk1",
+		gt.File("a.go", "strings"),
+	)
+	// Include some non-go files that sort before and after the go file.
+	// Triggers an edge case where the package wasn't added.
+	g.Setup("co2/pk1",
+		gt.FilePkgBuild("a.go", "main_test", "", "testing"),
+		gt.FilePkgBuild("b.go", "main", "", "fmt"),
+	)
+	g.In("co1")
+	c := ctx(g)
+	list(g, c, "before", `
+ l  co1/pk1 < []
+ s  strings < ["co1/pk1"]
+`)
+	g.Check(c.ModifyImport(pkg("co2/pk1"), AddUpdate))
+	g.Check(c.Alter())
+	g.Check(c.WriteVendorFile())
+
+	list(g, c, "after", `
+pv  co1/vendor/co2/pk1 [co2/pk1] < []
+ l  co1/pk1 < []
+ s  fmt < ["co1/vendor/co2/pk1"]
+ s  strings < ["co1/pk1"]
+ s  testing < ["co1/vendor/co2/pk1"]
+`)
+
+	c.IgnoreBuild("test")
+
+	list(g, c, "ignore test", `
+pv  co1/vendor/co2/pk1 [co2/pk1] < []
+ l  co1/pk1 < []
+ s  fmt < ["co1/vendor/co2/pk1"]
+ s  strings < ["co1/pk1"]
+`)
+
+}
+
 func TestUpdate(t *testing.T) {
 	g := gt.New(t)
 	defer g.Clean()
diff --git a/context/resolve.go b/context/resolve.go
index f484a61..8b2ebd9 100644
--- a/context/resolve.go
+++ b/context/resolve.go
@@ -72,15 +72,20 @@ func (ctx *Context) getFileTags(pathname string, f *ast.File) (tags, imports []s
 			return nil, nil, nil
 		}
 	}
+	tags = make([]string, 0, 6)
+	if strings.HasSuffix(f.Name.Name, "_test") {
+		tags = append(tags, "test")
+	}
+	pkgNameNormalized := strings.TrimSuffix(f.Name.Name, "_test")
+
 	// Files with package name "documentation" should be ignored, per go build tool.
-	if f.Name.Name == "documentation" {
+	if pkgNameNormalized == "documentation" {
 		return nil, nil, nil
 	}
 
 	filename := filenameExt[:len(filenameExt)-3]
 
 	l := strings.Split(filename, "_")
-	tags = make([]string, 0, 6)
 
 	if n := len(l); n > 1 && l[n-1] == "test" {
 		l = l[:n-1]
@@ -156,9 +161,10 @@ func (ctx *Context) addFileImports(pathname, gopath string) (*Package, error) {
 	if f == nil {
 		return nil, nil
 	}
+	pkgNameNormalized := strings.TrimSuffix(f.Name.Name, "_test")
 
 	// Files with package name "documentation" should be ignored, per go build tool.
-	if f.Name.Name == "documentation" {
+	if pkgNameNormalized == "documentation" {
 		return nil, nil
 	}
 
@@ -185,7 +191,7 @@ func (ctx *Context) addFileImports(pathname, gopath string) (*Package, error) {
 			Location: LocationUnknown,
 			Presence: PresenceFound,
 		}
-		if f.Name.Name == "main" {
+		if pkgNameNormalized == "main" {
 			status.Type = TypeProgram
 		}
 		pkg = ctx.setPackage(dir, importPath, importPath, gopath, status)
diff --git a/context/rewrite.go b/context/rewrite.go
index d58879a..3ace9f2 100644
--- a/context/rewrite.go
+++ b/context/rewrite.go
@@ -111,8 +111,9 @@ func (ctx *Context) rewrite() error {
 		if f == nil {
 			return nil
 		}
+		pkgNameNormalized := strings.TrimSuffix(f.Name.Name, "_test")
 		// Files with package name "documentation" should be ignored, per go build tool.
-		if f.Name.Name == "documentation" {
+		if pkgNameNormalized == "documentation" {
 			return nil
 		}
 
diff --git a/internal/gt/gopath.go b/internal/gt/gopath.go
index 736168a..f0cf92b 100644
--- a/internal/gt/gopath.go
+++ b/internal/gt/gopath.go
@@ -116,23 +116,20 @@ func (g *GopathTest) Check(err error) {
 
 type FileSpec struct {
 	Pkg     string
+	PkgName string
 	Name    string
 	Imports []string
 	Build   string
 }
 
 var fileSpecFile = template.Must(template.New("").Funcs(map[string]interface{}{
-	"pkg": func(s string) string {
-		_, pkg := path.Split(s)
-		return pkg
-	},
 	"imp": func(s string) string {
 		return "`" + s + "`"
 	},
 }).Parse(` {{if .Build}}
 // +build {{.Build}}
 {{end}}
-package {{.Pkg|pkg}}
+package {{.PkgName}}
 
 import (
 {{range .Imports}}	{{.|imp}}
@@ -151,12 +148,18 @@ func File(name string, imports ...string) FileSpec {
 func FileBuild(name, build string, imports ...string) FileSpec {
 	return FileSpec{Name: name, Build: build, Imports: imports}
 }
+func FilePkgBuild(name, pkgName, build string, imports ...string) FileSpec {
+	return FileSpec{Name: name, PkgName: pkgName, Build: build, Imports: imports}
+}
 
 func (g *GopathTest) Setup(at string, files ...FileSpec) {
 	var err error
 	pkg := g.mksrc(at)
 	for _, f := range files {
 		f.Pkg = at
+		if len(f.PkgName) == 0 {
+			_, f.PkgName = path.Split(f.Pkg)
+		}
 		p := filepath.Join(pkg, f.Name)
 		err = ioutil.WriteFile(p, f.Bytes(), 0600)
 		if err != nil {