diff --git a/core/lib/exportData.js b/core/lib/exportData.js
new file mode 100644
index 000000000..0503c7aad
--- /dev/null
+++ b/core/lib/exportData.js
@@ -0,0 +1,54 @@
+"use strict";
+
+const eol = require('os').EOL;
+const path = require('path');
+const _ = require('lodash');
+
+const ae = require('./annotation_exporter');
+
+let fs = require('fs-extra'); //eslint-disable-line prefer-const
+
+/**
+ * Write out our pattern information for use by the front end
+ * @param patternlab - global data store
+ */
+module.exports = function (patternlab) {
+
+  const annotation_exporter = new ae(patternlab);
+
+  const paths = patternlab.config.paths;
+
+  //write out the data
+  let output = '';
+
+  //config
+  output += 'var config = ' + JSON.stringify(patternlab.config) + ';\n';
+
+  //ishControls
+  output += 'var ishControls = {"ishControlsHide":' + JSON.stringify(patternlab.config.ishControlsHide) + '};' + eol;
+
+  //navItems
+  output += 'var navItems = {"patternTypes": ' + JSON.stringify(patternlab.patternTypes) + ', "ishControlsHide": ' + JSON.stringify(patternlab.config.ishControlsHide) + '};' + eol;
+
+  //patternPaths
+  output += 'var patternPaths = ' + JSON.stringify(patternlab.patternPaths) + ';' + eol;
+
+  //viewAllPaths
+  output += 'var viewAllPaths = ' + JSON.stringify(patternlab.viewAllPaths) + ';' + eol;
+
+  //plugins
+  output += 'var plugins = ' + JSON.stringify(patternlab.plugins || []) + ';' + eol;
+
+  //smaller config elements
+  output += 'var defaultShowPatternInfo = ' + (patternlab.config.defaultShowPatternInfo ? patternlab.config.defaultShowPatternInfo : 'false') + ';' + eol;
+  output += 'var defaultPattern = "' + (patternlab.config.defaultPattern ? patternlab.config.defaultPattern : 'all') + '";' + eol;
+
+  //annotations
+  const annotationsJSON = annotation_exporter.gather();
+  const annotations = 'var comments = { "comments" : ' + JSON.stringify(annotationsJSON) + '};';
+  fs.outputFileSync(path.resolve(paths.public.annotations, 'annotations.js'), annotations);
+
+  //write all output to patternlab-data
+  fs.outputFileSync(path.resolve(paths.public.data, 'patternlab-data.js'), output);
+  return output;
+};
diff --git a/core/lib/ui_builder.js b/core/lib/ui_builder.js
index ea91ca4a6..c81d7679b 100644
--- a/core/lib/ui_builder.js
+++ b/core/lib/ui_builder.js
@@ -2,9 +2,7 @@
 
 const path = require('path');
 const _ = require('lodash');
-const eol = require('os').EOL;
 
-const ae = require('./annotation_exporter');
 const of = require('./object_factory');
 const Pattern = of.Pattern;
 const logger = require('./log');
@@ -13,6 +11,7 @@ const logger = require('./log');
 let render = require('./render'); //eslint-disable-line prefer-const
 let fs = require('fs-extra'); //eslint-disable-line prefer-const
 let buildFooter = require('./buildFooter'); //eslint-disable-line prefer-const
+let exportData = require('./exportData'); //eslint-disable-line prefer-const
 
 const ui_builder = function () {
 
@@ -566,48 +565,6 @@ const ui_builder = function () {
     });
   }
 
-  /**
-   * Write out our pattern information for use by the front end
-   * @param patternlab - global data store
-     */
-  function exportData(patternlab) {
-    const annotation_exporter = new ae(patternlab);
-    const paths = patternlab.config.paths;
-
-    //write out the data
-    let output = '';
-
-    //config
-    output += 'var config = ' + JSON.stringify(patternlab.config) + ';\n';
-
-    //ishControls
-    output += 'var ishControls = {"ishControlsHide":' + JSON.stringify(patternlab.config.ishControlsHide) + '};' + eol;
-
-    //navItems
-    output += 'var navItems = {"patternTypes": ' + JSON.stringify(patternlab.patternTypes) + ', "ishControlsHide": ' + JSON.stringify(patternlab.config.ishControlsHide) + '};' + eol;
-
-    //patternPaths
-    output += 'var patternPaths = ' + JSON.stringify(patternlab.patternPaths) + ';' + eol;
-
-    //viewAllPaths
-    output += 'var viewAllPaths = ' + JSON.stringify(patternlab.viewAllPaths) + ';' + eol;
-
-    //plugins
-    output += 'var plugins = ' + JSON.stringify(patternlab.plugins || []) + ';' + eol;
-
-    //smaller config elements
-    output += 'var defaultShowPatternInfo = ' + (patternlab.config.defaultShowPatternInfo ? patternlab.config.defaultShowPatternInfo : 'false') + ';' + eol;
-    output += 'var defaultPattern = "' + (patternlab.config.defaultPattern ? patternlab.config.defaultPattern : 'all') + '";' + eol;
-
-    //write all output to patternlab-data
-    fs.outputFileSync(path.resolve(paths.public.data, 'patternlab-data.js'), output);
-
-    //annotations
-    const annotationsJSON = annotation_exporter.gather();
-    const annotations = 'var comments = { "comments" : ' + JSON.stringify(annotationsJSON) + '};';
-    fs.outputFileSync(path.resolve(paths.public.annotations, 'annotations.js'), annotations);
-  }
-
   /**
    * Reset any global data we use between builds to guard against double adding things
    */
diff --git a/test/exportData_tests.js b/test/exportData_tests.js
new file mode 100644
index 000000000..29fdf71d6
--- /dev/null
+++ b/test/exportData_tests.js
@@ -0,0 +1,66 @@
+"use strict";
+
+const path = require('path');
+const tap = require('tap');
+const rewire = require("rewire");
+
+const exportData = rewire('../core/lib/exportData');
+const util = require('./util/test_utils.js');
+
+const testPatternsPath = path.resolve(__dirname, 'files', '_patterns');
+
+const fsMock = {
+  outputFileSync: function (path, content) { /* INTENTIONAL NOOP */},
+};
+
+//set our mocks in place of usual require()
+exportData.__set__({
+  'fs': fsMock,
+});
+
+const patternlab = util.fakePatternLab(testPatternsPath);
+const result = exportData(patternlab);
+
+tap.test('exportData exports config', function (test) {
+  test.equals(result.indexOf('config') > -1, true);
+  test.equals(result.indexOf('paths') > -1, true);
+  test.equals(result.indexOf('theme') > -1, true);
+  test.end();
+});
+
+tap.test('exportData exports ishControls', function (test) {
+  test.equals(result.indexOf('ishControlsHide') > -1, true);
+  test.end();
+});
+
+tap.test('exportData exports navItems', function (test) {
+  test.equals(result.indexOf('patternTypes') > -1, true);
+  test.end();
+});
+
+tap.test('exportData exports patternPaths', function (test) {
+  test.equals(result.indexOf('patternPaths') > -1, true);
+  test.end();
+});
+
+tap.test('exportData exports viewAllPaths', function (test) {
+  test.equals(result.indexOf('viewAllPaths') > -1, true);
+  test.end();
+});
+
+tap.test('exportData exports plugins', function (test) {
+  test.equals(result.indexOf('plugins') > -1, true);
+  test.end();
+});
+
+tap.test('exportData exports defaultShowPatternInfo', function (test) {
+  test.equals(result.indexOf('defaultShowPatternInfo') > -1, true);
+  test.equals(result.indexOf('"defaultShowPatternInfo":false') > -1, true);
+  test.end();
+});
+
+tap.test('exportData exports defaultPattern', function (test) {
+  test.equals(result.indexOf('defaultPattern') > -1, true);
+  test.equals(result.indexOf('"defaultPattern":"all"') > -1, true);
+  test.end();
+});