diff --git a/cors/generate_test.go b/cors/generate_test.go
index 5f6b6655b..a5df5f227 100644
--- a/cors/generate_test.go
+++ b/cors/generate_test.go
@@ -9,7 +9,6 @@ import (
 	"goa.design/goa/v3/codegen"
 	"goa.design/goa/v3/codegen/service"
 	"goa.design/goa/v3/eval"
-	"goa.design/goa/v3/expr"
 	httpcodegen "goa.design/goa/v3/http/codegen"
 
 	"goa.design/plugins/v3/cors"
@@ -43,11 +42,11 @@ func NewCORSHandler() http.Handler {
 	}
 	for _, c := range cases {
 		t.Run(c.Name, func(t *testing.T) {
-			httpcodegen.RunHTTPDSL(t, c.DSL)
-			services := httpcodegen.NewServicesData(service.NewServicesData(expr.Root), expr.Root.API.HTTP)
+			root := httpcodegen.RunHTTPDSL(t, c.DSL)
+			services := httpcodegen.NewServicesData(service.NewServicesData(root), root.API.HTTP)
 			fs := httpcodegen.ServerFiles("", services)
 			require.Len(t, fs, c.CodeGenCount)
-			cors.Generate("", []eval.Root{expr.Root}, fs)
+			cors.Generate("", []eval.Root{root}, fs)
 			expectedCodeIndex := -1
 			for _, f := range fs {
 				if filepath.Base(f.Path) != "server.go" {
diff --git a/goakit/encode_decode_files_test.go b/goakit/encode_decode_files_test.go
index afa430b43..02296a98b 100644
--- a/goakit/encode_decode_files_test.go
+++ b/goakit/encode_decode_files_test.go
@@ -7,7 +7,6 @@ import (
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 	"goa.design/goa/v3/codegen"
-	"goa.design/goa/v3/expr"
 	httpcodegen "goa.design/goa/v3/http/codegen"
 
 	"goa.design/plugins/v3/goakit/testdata"
@@ -67,8 +66,8 @@ func TestServerEncodeDecode(t *testing.T) {
 	}
 	for name, c := range cases {
 		t.Run(name, func(t *testing.T) {
-			httpcodegen.RunHTTPDSL(t, c.DSL)
-			fs := EncodeDecodeFiles("", expr.Root)
+			root := httpcodegen.RunHTTPDSL(t, c.DSL)
+			fs := EncodeDecodeFiles("", root)
 			require.Len(t, fs, 2)
 			var found bool
 			for _, f := range fs {
@@ -126,8 +125,8 @@ func TestClientEncodeDecode(t *testing.T) {
 	}
 	for name, c := range cases {
 		t.Run(name, func(t *testing.T) {
-			httpcodegen.RunHTTPDSL(t, c.DSL)
-			fs := EncodeDecodeFiles("", expr.Root)
+			root := httpcodegen.RunHTTPDSL(t, c.DSL)
+			fs := EncodeDecodeFiles("", root)
 			require.Len(t, fs, 2)
 			var found bool
 			for _, f := range fs {
diff --git a/goakit/generate_test.go b/goakit/generate_test.go
index 945a57b26..9f57f2f01 100644
--- a/goakit/generate_test.go
+++ b/goakit/generate_test.go
@@ -10,7 +10,6 @@ import (
 	"goa.design/goa/v3/codegen"
 	"goa.design/goa/v3/codegen/generator"
 	"goa.design/goa/v3/eval"
-	"goa.design/goa/v3/expr"
 	httpcodegen "goa.design/goa/v3/http/codegen"
 	"goa.design/plugins/v3/goakit/testdata"
 )
@@ -25,8 +24,8 @@ func TestGenerate(t *testing.T) {
 	}
 	for name, c := range cases {
 		t.Run(name, func(t *testing.T) {
-			httpcodegen.RunHTTPDSL(t, c.DSL)
-			roots := []eval.Root{expr.Root}
+			root := httpcodegen.RunHTTPDSL(t, c.DSL)
+			roots := []eval.Root{root}
 			files := generateFiles(t, roots)
 			newFiles, err := Generate("", roots, files)
 			if err != nil {
@@ -49,8 +48,8 @@ func TestGoakitify(t *testing.T) {
 	}
 	for name, dsl := range cases {
 		t.Run(name, func(t *testing.T) {
-			httpcodegen.RunHTTPDSL(t, dsl)
-			roots := []eval.Root{expr.Root}
+			root := httpcodegen.RunHTTPDSL(t, dsl)
+			roots := []eval.Root{root}
 			files := generateFiles(t, roots)
 			newFiles, err := Goakitify("", roots, files)
 			require.NoError(t, err)
@@ -111,8 +110,8 @@ func TestGoakitifyExample(t *testing.T) {
 	}
 	for name, c := range cases {
 		t.Run(name, func(t *testing.T) {
-			httpcodegen.RunHTTPDSL(t, c.DSL)
-			roots := []eval.Root{expr.Root}
+			root := httpcodegen.RunHTTPDSL(t, c.DSL)
+			roots := []eval.Root{root}
 			files := generateExamples(t, roots)
 			files, err := GoakitifyExample("", roots, files)
 			require.NoError(t, err)
diff --git a/goakit/mount_files_test.go b/goakit/mount_files_test.go
index ca164c3fa..b9030dd7c 100644
--- a/goakit/mount_files_test.go
+++ b/goakit/mount_files_test.go
@@ -3,7 +3,6 @@ package goakit
 import (
 	"testing"
 
-	"goa.design/goa/v3/expr"
 	httpcodegen "goa.design/goa/v3/http/codegen"
 	"goa.design/plugins/v3/goakit/testdata"
 )
@@ -49,8 +48,8 @@ func TestMountFiles(t *testing.T) {
 	}
 	for name, c := range cases {
 		t.Run(name, func(t *testing.T) {
-			httpcodegen.RunHTTPDSL(t, c.DSL)
-			fs := MountFiles(expr.Root)
+			root := httpcodegen.RunHTTPDSL(t, c.DSL)
+			fs := MountFiles(root)
 			if len(fs) != 1 {
 				t.Fatalf("got %d files, expected 1", len(fs))
 			}
diff --git a/i18n/generate_test.go b/i18n/generate_test.go
index 30f2d5ada..f556e97b5 100644
--- a/i18n/generate_test.go
+++ b/i18n/generate_test.go
@@ -26,9 +26,9 @@ func TestPrepare(t *testing.T) {
 	for _, c := range cases {
 		t.Run(c.Name, func(t *testing.T) {
 			os.Setenv("GOA_I18N", c.Locales)
-			httpcodegen.RunHTTPDSL(t, c.DSL)
+			root := httpcodegen.RunHTTPDSL(t, c.DSL)
 
-			roots, _ := eval.Context.Roots()
+			roots := []eval.Root{root}
 
 			// Expect Description to be empty
 			checkExpr(roots, &expr.ServiceExpr{}, func(se interface{}) {
@@ -63,11 +63,11 @@ func checkExpr(roots []eval.Root, t interface{}, cb func(se interface{})) {
 func TestGenerate(t *testing.T) {
 	os.Setenv("GOA_I18N", "en,nl")
 
-	httpcodegen.RunHTTPDSL(t, testdata.SimpleI18nDSL)
-	roots, _ := eval.Context.Roots()
+	root := httpcodegen.RunHTTPDSL(t, testdata.SimpleI18nDSL)
+	roots := []eval.Root{root}
 	i18n.Prepare("", roots)
 
-	fs, _ := httpcodegen.OpenAPIFiles(expr.Root)
+	fs, _ := httpcodegen.OpenAPIFiles(root)
 	gfs, _ := i18n.Generate("", roots, fs)
 
 	if len(gfs) != 8 {