diff --git a/BUILD.gn b/BUILD.gn
index 450a46c..53f4644 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -1957,7 +1957,6 @@
     "testing/embedder_test.h",
     "testing/embedder_test_mock_delegate.h",
     "testing/embedder_test_timer_handling_delegate.h",
-    "xfa/fxfa/parser/cxfa_simple_parser_embeddertest.cpp",
   ]
   deps = [
     ":pdfium",
@@ -1978,6 +1977,14 @@
     deps += [ ":fxjs" ]
     configs += [ "//v8:external_startup_data" ]
   }
+  if (pdf_enable_xfa) {
+    sources += [
+      "testing/xfa_js_embedder_test.cpp",
+      "testing/xfa_js_embedder_test.h",
+      "xfa/fxfa/fm2js/cxfa_fm2jscontext_embeddertest.cpp",
+      "xfa/fxfa/parser/cxfa_simple_parser_embeddertest.cpp",
+    ]
+  }
   if (is_android) {
     ignore_all_data_deps = true
     use_raw_android_executable = true
diff --git a/testing/DEPS b/testing/DEPS
index 5adeb41..d0dc172 100644
--- a/testing/DEPS
+++ b/testing/DEPS
@@ -1,6 +1,8 @@
 include_rules = [
   '+core',
+  '+fpdfsdk',
   '+fxjs',
   '+public',
   '+v8',
+  '+xfa'
 ]
diff --git a/testing/embedder_test.cpp b/testing/embedder_test.cpp
index 1baeb57..bf00c11 100644
--- a/testing/embedder_test.cpp
+++ b/testing/embedder_test.cpp
@@ -179,6 +179,8 @@
     }
   }
 
+  SetupFormFillEnvironment();
+
 #ifdef PDF_ENABLE_XFA
   int docType = DOCTYPE_PDF;
   if (FPDF_HasXFAField(document_, &docType)) {
@@ -188,7 +190,6 @@
 #endif  // PDF_ENABLE_XFA
 
   (void)FPDF_GetDocPermissions(document_);
-  SetupFormFillEnvironment();
   return true;
 }
 
@@ -197,6 +198,7 @@
   memset(platform, 0, sizeof(IPDF_JSPLATFORM));
   platform->version = 2;
   platform->app_alert = AlertTrampoline;
+  platform->m_isolate = external_isolate_;
 
   FPDF_FORMFILLINFO* formfillinfo = static_cast<FPDF_FORMFILLINFO*>(this);
   memset(formfillinfo, 0, sizeof(FPDF_FORMFILLINFO));
diff --git a/testing/resources/simple_xfa.pdf b/testing/resources/simple_xfa.pdf
new file mode 100644
index 0000000..ef8eb7d
--- /dev/null
+++ b/testing/resources/simple_xfa.pdf
Binary files differ
diff --git a/testing/xfa_js_embedder_test.cpp b/testing/xfa_js_embedder_test.cpp
new file mode 100644
index 0000000..d72e876
--- /dev/null
+++ b/testing/xfa_js_embedder_test.cpp
@@ -0,0 +1,69 @@
+// Copyright 2017 PDFium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "testing/xfa_js_embedder_test.h"
+
+#include <string>
+
+#include "fpdfsdk/fpdfxfa/cpdfxfa_context.h"
+#include "fpdfsdk/fsdk_define.h"
+#include "testing/gtest/include/gtest/gtest.h"
+#include "third_party/base/ptr_util.h"
+#include "xfa/fxfa/parser/cxfa_scriptcontext.h"
+
+XFAJSEmbedderTest::XFAJSEmbedderTest()
+    : array_buffer_allocator_(pdfium::MakeUnique<FXJS_ArrayBufferAllocator>()) {
+}
+
+XFAJSEmbedderTest::~XFAJSEmbedderTest() {}
+
+void XFAJSEmbedderTest::SetUp() {
+  v8::Isolate::CreateParams params;
+  params.array_buffer_allocator = array_buffer_allocator_.get();
+  isolate_ = v8::Isolate::New(params);
+  ASSERT_TRUE(isolate_ != nullptr);
+
+  EmbedderTest::SetExternalIsolate(isolate_);
+  EmbedderTest::SetUp();
+}
+
+void XFAJSEmbedderTest::TearDown() {
+  value_ = nullptr;
+  script_context_ = nullptr;
+
+  EmbedderTest::TearDown();
+
+  isolate_->Dispose();
+  isolate_ = nullptr;
+}
+
+bool XFAJSEmbedderTest::OpenDocument(const std::string& filename,
+                                     const char* password,
+                                     bool must_linearize) {
+  if (!EmbedderTest::OpenDocument(filename, password, must_linearize))
+    return false;
+
+  script_context_ = UnderlyingFromFPDFDocument(document())
+                        ->GetXFADoc()
+                        ->GetXFADoc()
+                        ->GetScriptContext();
+  return true;
+}
+
+bool XFAJSEmbedderTest::Execute(const CFX_ByteStringC& input) {
+  value_ = pdfium::MakeUnique<CFXJSE_Value>(GetIsolate());
+  if (script_context_->RunScript(XFA_SCRIPTLANGTYPE_Formcalc,
+                                 CFX_WideString::FromUTF8(input).AsStringC(),
+                                 value_.get(), nullptr)) {
+    return true;
+  }
+
+  CFXJSE_Value msg(GetIsolate());
+  value_->GetObjectPropertyByIdx(1, &msg);
+  EXPECT_TRUE(msg.IsString());
+
+  fprintf(stderr, "JS: %.*s\n", input.GetLength(), input.c_str());
+  fprintf(stderr, "JS ERROR: %ls\n", msg.ToWideString().c_str());
+  return false;
+}
diff --git a/testing/xfa_js_embedder_test.h b/testing/xfa_js_embedder_test.h
new file mode 100644
index 0000000..62c3597
--- /dev/null
+++ b/testing/xfa_js_embedder_test.h
@@ -0,0 +1,41 @@
+// Copyright 2017 PDFium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef TESTING_XFA_JS_EMBEDDER_TEST_H_
+#define TESTING_XFA_JS_EMBEDDER_TEST_H_
+
+#include <memory>
+#include <string>
+
+#include "fxjs/cfxjse_value.h"
+#include "fxjs/fxjs_v8.h"
+#include "testing/embedder_test.h"
+
+class CXFA_ScriptContext;
+
+class XFAJSEmbedderTest : public EmbedderTest {
+ public:
+  XFAJSEmbedderTest();
+  ~XFAJSEmbedderTest() override;
+
+  void SetUp() override;
+  void TearDown() override;
+
+  bool OpenDocument(const std::string& filename,
+                    const char* password = nullptr,
+                    bool must_linearize = false) override;
+
+  v8::Isolate* GetIsolate() const { return isolate_; }
+
+  bool Execute(const CFX_ByteStringC& input);
+  CFXJSE_Value* GetValue() const { return value_.get(); }
+
+ private:
+  std::unique_ptr<FXJS_ArrayBufferAllocator> array_buffer_allocator_;
+  std::unique_ptr<CFXJSE_Value> value_;
+  v8::Isolate* isolate_;
+  CXFA_ScriptContext* script_context_;
+};
+
+#endif  // TESTING_XFA_JS_EMBEDDER_TEST_H_
diff --git a/xfa/fxfa/fm2js/cxfa_fm2jscontext_embeddertest.cpp b/xfa/fxfa/fm2js/cxfa_fm2jscontext_embeddertest.cpp
new file mode 100644
index 0000000..a94e8a9
--- /dev/null
+++ b/xfa/fxfa/fm2js/cxfa_fm2jscontext_embeddertest.cpp
@@ -0,0 +1,39 @@
+// Copyright 2017 PDFium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "testing/gtest/include/gtest/gtest.h"
+#include "testing/xfa_js_embedder_test.h"
+
+class FM2JSContextEmbedderTest : public XFAJSEmbedderTest {};
+
+TEST_F(FM2JSContextEmbedderTest, TranslateEmpty) {
+  ASSERT_TRUE(OpenDocument("simple_xfa.pdf"));
+
+  const char input[] = "";
+  EXPECT_TRUE(Execute(input));
+  // TODO(dsinclair): This should probably throw as a blank formcalc script
+  // is invalid.
+}
+
+TEST_F(FM2JSContextEmbedderTest, TranslateNumber) {
+  ASSERT_TRUE(OpenDocument("simple_xfa.pdf"));
+
+  const char input[] = "123";
+  EXPECT_TRUE(Execute(input));
+
+  CFXJSE_Value* value = GetValue();
+  ASSERT_TRUE(value->IsNumber());
+  EXPECT_EQ(123, value->ToInteger());
+}
+
+TEST_F(FM2JSContextEmbedderTest, Add) {
+  ASSERT_TRUE(OpenDocument("simple_xfa.pdf"));
+
+  const char input[] = "123 + 456";
+  EXPECT_TRUE(Execute(input));
+
+  CFXJSE_Value* value = GetValue();
+  ASSERT_TRUE(value->IsNumber());
+  EXPECT_EQ(579, value->ToInteger());
+}