diff --git a/package.json b/package.json
index 41308cf5e..f43578ac3 100644
--- a/package.json
+++ b/package.json
@@ -42,7 +42,6 @@
     "license": "gulp checkLicenses",
     "lint": "eslint .",
     "package": "gulp package",
-    "prepare": "npm run package",
     "publish": "gulp publish",
     "publish:beta": "gulp publishBeta",
     "recompile": "gulp recompile",
diff --git a/scripts/gulpfiles/package_tasks.js b/scripts/gulpfiles/package_tasks.js
index 6fef12152..6b791d2e6 100644
--- a/scripts/gulpfiles/package_tasks.js
+++ b/scripts/gulpfiles/package_tasks.js
@@ -19,18 +19,11 @@ var path = require('path');
 var fs = require('fs');
 var rimraf = require('rimraf');
 var {getPackageJson} = require('./helper_tasks');
-var {RELEASE_DIR} = require('./config');
+var {BUILD_DIR, RELEASE_DIR} = require('./config');
 
 // Path to template files for gulp-umd.
 const TEMPLATE_DIR = 'scripts/package/templates';
 
-// Path from which to pull files to package.
-//
-// TODO(cpcallen): Use BUILD_DIR from config.js once release_tasks are
-// updated to do build-package-release all in one go, instead of doing
-// build-checkin and then package-release as separate steps.
-var BUILD_DIR = '.';
-
 /**
  * A helper method for wrapping a file into a Universal Module Definition.
  * @param {string} namespace The export namespace.
@@ -59,6 +52,41 @@ function packageCommonJS(namespace, dependencies) {
   });
 };
 
+// Sanity check that the BUILD_DIR directory exists, and that certain
+// files are in it.
+function checkBuildDir(done) {
+  // Check that directory exists.
+  if (!fs.existsSync(BUILD_DIR)) {
+    done(new Error(`The ${BUILD_DIR} directory does not exist.  ` +
+        'Have both packageTasks.build and typingsTasks.typings been run?'));
+    return;
+  }
+  // Check files built by buildTasks.build exist in BUILD_DIR.
+  for (const fileName of [
+    'blockly_compressed.js',  // buildTasks.buildCompressed
+    'blocks_compressed.js',  // buildTasks.buildBlocks
+    'javascript_compressed.js',  // buildTasks.buildGenerators
+    'msg/js/en.js',  // buildTaks.buildLangfiles
+  ]) {
+    if (!fs.existsSync(`${BUILD_DIR}/${fileName}`)) {
+      done(new Error(
+          `Your ${BUILD_DIR} directory does not contain ${fileName}.  ` +
+          'Has packageTasks.build been run?  Try "npm run build".'));
+      return;
+    }
+  }
+  // Check files built by typings.typings exist in BUILD_DIR.
+  for (const fileName of ['blockly.d.ts', 'msg/en.d.ts']) {
+    if (!fs.existsSync(`${BUILD_DIR}/${fileName}`)) {
+      done(new Error(
+          `Your ${BUILD_DIR} directory does not contain ${fileName}.  ` +
+          'Has typings.typings been run?  Try "npm run typings".'));
+      return;
+    }
+  }
+  done();
+}
+
 /**
  * This task copies source files into the release directory.
  */
@@ -321,7 +349,7 @@ function packageLocales() {
 function packageUMDBundle() {
   var srcs = [
     `${BUILD_DIR}/blockly_compressed.js`,
-    'msg/js/en.js',
+    `${BUILD_DIR}/msg/js/en.js`,
     `${BUILD_DIR}/blocks_compressed.js`,
     `${BUILD_DIR}/javascript_compressed.js`,
   ];
@@ -360,7 +388,7 @@ function packageJSON(cb) {
  */
 function packageReadme() {
   return gulp.src('scripts/package/README.md')
-    .pipe(gulp.dest(`${RELEASE_DIR}`));
+    .pipe(gulp.dest(RELEASE_DIR));
 };
 
 /**
@@ -369,9 +397,18 @@ function packageReadme() {
  * referenced in package.json in the types property.
  */
 function packageDTS() {
-  return gulp.src(['typings/*.d.ts', 'typings/msg/*.d.ts'],
-                  {base: './typings'})
-    .pipe(gulp.dest(`${RELEASE_DIR}`));
+  const handwrittenSrcs = [
+    'typings/*.d.ts',
+    '!typings/blockly.d.ts',  // Exclude checked-in copy of blockly.d.ts.
+    'typings/msg/msg.d.ts',
+  ];
+  const builtSrcs = [
+    `${BUILD_DIR}/blockly.d.ts`,  // Use freshly-built one instead.
+    `${BUILD_DIR}/msg/*.d.ts`,
+  ];
+  return gulp.src(handwrittenSrcs, {base: 'typings'})
+      .pipe(gulp.src(builtSrcs, {base: BUILD_DIR}))
+      .pipe(gulp.dest(RELEASE_DIR));
 };
 
 /**
@@ -390,6 +427,7 @@ function cleanReleaseDir(done) {
  * them into the release directory.
  */
 const package = gulp.series(
+    checkBuildDir,
     cleanReleaseDir,
     gulp.parallel(
         packageIndex,
diff --git a/scripts/gulpfiles/release_tasks.js b/scripts/gulpfiles/release_tasks.js
index c4480f06c..a55edd380 100644
--- a/scripts/gulpfiles/release_tasks.js
+++ b/scripts/gulpfiles/release_tasks.js
@@ -149,8 +149,18 @@ function updateBetaVersion(done) {
   done();
 }
 
+// Build Blockly and prepare to check in the resulting built files.
+const recompile = gulp.series(
+  buildTasks.cleanBuildDir,
+  buildTasks.build,
+  buildTasks.checkinBuilt,
+  typings.typings,
+  typings.checkinTypings,
+  );
+
 // Package and publish to npm.
 const publish = gulp.series(
+  recompile,
   packageTasks.package,
   checkBranch,
   checkReleaseDir,
@@ -160,30 +170,25 @@ const publish = gulp.series(
 // Publish a beta version of Blockly.
 const publishBeta = gulp.series(
   updateBetaVersion,
-  buildTasks.cleanBuildDir,
-  buildTasks.build,
-  buildTasks.checkinBuilt,
+  recompile,
   packageTasks.package,
   checkBranch,
   checkReleaseDir,
   loginAndPublishBeta
 );
 
-// Switch to a new branch, update the version number, and build Blockly.
-const recompile = gulp.series(
+// Switch to a new branch, update the version number, build Blockly
+// and check in the resulting built files.
+const recompileDevelop = gulp.series(
   gitTasks.syncDevelop(),
   gitTasks.createRebuildBranch,
   updateVersionPrompt,
-  buildTasks.cleanBuildDir,
-  buildTasks.build,
-  buildTasks.checkinBuilt,
-  typings.typings,
-  typings.checkinTypings,
+  recompile,
   gitTasks.pushRebuildBranch
   );
 
 module.exports = {
-  recompile: recompile,
+  recompile: recompileDevelop,
   publishBeta: publishBeta,
   publish: publish
 }
diff --git a/tests/run_all_tests.sh b/tests/run_all_tests.sh
index 5107a6ebf..f6c7c0f8c 100755
--- a/tests/run_all_tests.sh
+++ b/tests/run_all_tests.sh
@@ -51,14 +51,15 @@ run_test_command () {
 # Lint the codebase.
 run_test_command "eslint" "eslint ."
 
-# Run the closure compiler.
-run_test_command "compile" "npm run build"
+# Run the full usual build process.
+run_test_command "build" "npm run build"
 
-# Run the closure compiler ensuring there are no compiler warnings / errors.
-run_test_command "compile:warnings" "npm run build:debug"
+# Run the debug build, to ensure there are no closure compiler
+# warnings / errors.
+run_test_command "build:debug" "npm run build:debug"
 
 # Generate TypeScript typings and ensure there are no errors.
-run_test_command "typings" "tests/scripts/compile_typings.sh"
+run_test_command "typings" "npm run typings"
 
 # Check the sizes of built files for unexpected growth.
 run_test_command "metadata" "tests/scripts/check_metadata.sh"
@@ -69,6 +70,9 @@ run_test_command "mocha" "node tests/mocha/run_mocha_tests_in_browser.js"
 # Run generator tests inside a browser and check the results.
 run_test_command "generators" "tests/scripts/run_generators.sh"
 
+# Run the package build process, as Node tests depend on it.
+run_test_command "package" "npm run package"
+
 # Run Node tests.
 run_test_command "node" "./node_modules/.bin/mocha tests/node --config tests/node/.mocharc.js"