diff --git a/src/core/fonts.js b/src/core/fonts.js
index 83522b3df..f5722983f 100644
--- a/src/core/fonts.js
+++ b/src/core/fonts.js
@@ -505,75 +505,6 @@ var ProblematicCharRanges = new Int32Array([
   0xFFF0, 0x10000
 ]);
 
-if (typeof PDFJSDev === 'undefined' || !PDFJSDev.test('PRODUCTION')) {
-  /**
-   * Used to validate the entries in `ProblematicCharRanges`, and to ensure that
-   * its total number of characters does not exceed the PUA (Private Use Area)
-   * length.
-   * @returns {Object} An object with {number} `numChars`, {number} `puaLength`,
-   *   and {number} `percentage` parameters.
-   */
-  var checkProblematicCharRanges = function checkProblematicCharRanges() {
-    function printRange(limits) {
-      return '[' + limits.lower.toString('16').toUpperCase() + ', ' +
-                   limits.upper.toString('16').toUpperCase() + ')';
-    }
-
-    var numRanges = ProblematicCharRanges.length;
-    if (numRanges % 2 !== 0) {
-      throw new Error('Char ranges must contain an even number of elements.');
-    }
-    var prevLimits, numChars = 0;
-    for (var i = 0; i < numRanges; i += 2) {
-      var limits = {
-        lower: ProblematicCharRanges[i],
-        upper: ProblematicCharRanges[i + 1],
-      };
-      if (!isInt(limits.lower) || !isInt(limits.upper)) {
-        throw new Error('Range endpoints must be integers: ' +
-                        printRange(limits));
-      }
-      if (limits.lower < 0 || limits.upper < 0) {
-        throw new Error('Range endpoints must be non-negative: ' +
-                        printRange(limits));
-      }
-      var range = limits.upper - limits.lower;
-      if (range < 1) {
-        throw new Error('Range must contain at least one element: ' +
-                        printRange(limits));
-      }
-      if (prevLimits) {
-        if (limits.lower < prevLimits.lower) {
-          throw new Error('Ranges must be sorted in ascending order: ' +
-                          printRange(limits) + ', ' + printRange(prevLimits));
-        }
-        if (limits.lower < prevLimits.upper) {
-          throw new Error('Ranges must not overlap: ' +
-                          printRange(limits) + ', ' + printRange(prevLimits));
-        }
-      }
-      prevLimits = {
-        lower: limits.lower,
-        upper: limits.upper,
-      };
-      // The current range is OK.
-      numChars += range;
-    }
-    var puaLength = (PRIVATE_USE_OFFSET_END + 1) - PRIVATE_USE_OFFSET_START;
-    if (numChars > puaLength) {
-      throw new Error('Total number of chars must not exceed the PUA length.');
-    }
-    return {
-      numChars: numChars,
-      puaLength: puaLength,
-      percentage: 100 * (numChars / puaLength),
-    };
-  };
-
-  exports.SEAC_ANALYSIS_ENABLED = SEAC_ANALYSIS_ENABLED;
-  exports.checkProblematicCharRanges = checkProblematicCharRanges;
-}
-
 /**
  * 'Font' is the class the outside world should use, it encapsulate all the font
  * decoding logics whatever type it is (assuming the font type is supported).
@@ -3436,10 +3367,14 @@ var CFFFont = (function CFFFontClosure() {
   }
 })();
 
+exports.SEAC_ANALYSIS_ENABLED = SEAC_ANALYSIS_ENABLED;
+exports.PRIVATE_USE_OFFSET_START = PRIVATE_USE_OFFSET_START;
+exports.PRIVATE_USE_OFFSET_END = PRIVATE_USE_OFFSET_END;
 exports.ErrorFont = ErrorFont;
 exports.Font = Font;
 exports.FontFlags = FontFlags;
 exports.IdentityToUnicodeMap = IdentityToUnicodeMap;
+exports.ProblematicCharRanges = ProblematicCharRanges;
 exports.ToUnicodeMap = ToUnicodeMap;
 exports.getFontType = getFontType;
 }));
diff --git a/test/unit/fonts_spec.js b/test/unit/fonts_spec.js
index 2d7cd3af4..eb92d1b01 100644
--- a/test/unit/fonts_spec.js
+++ b/test/unit/fonts_spec.js
@@ -16,16 +16,85 @@
 
 (function (root, factory) {
   if (typeof define === 'function' && define.amd) {
-    define('pdfjs-test/unit/fonts_spec', ['exports', 'pdfjs/core/fonts'],
-           factory);
+    define('pdfjs-test/unit/fonts_spec', ['exports', 'pdfjs/core/fonts',
+      'pdfjs/shared/util'], factory);
   } else if (typeof exports !== 'undefined') {
-    factory(exports, require('../../src/core/fonts.js'));
+    factory(exports, require('../../src/core/fonts.js'),
+      require('../../src/shared/util.js'));
   } else {
-    factory((root.pdfjsTestUnitFontsSpec = {}), root.pdfjsCoreFonts);
+    factory((root.pdfjsTestUnitFontsSpec = {}), root.pdfjsCoreFonts,
+      root.pdfjsSharedUtil);
   }
-}(this, function (exports, coreFonts) {
+}(this, function (exports, coreFonts, sharedUtil) {
 
-var checkProblematicCharRanges = coreFonts.checkProblematicCharRanges;
+var ProblematicCharRanges = coreFonts.ProblematicCharRanges;
+var PRIVATE_USE_OFFSET_START = coreFonts.PRIVATE_USE_OFFSET_START;
+var PRIVATE_USE_OFFSET_END = coreFonts.PRIVATE_USE_OFFSET_END;
+var isInt = sharedUtil.isInt;
+
+/**
+ * Used to validate the entries in `ProblematicCharRanges`, and to ensure that
+ * its total number of characters does not exceed the PUA (Private Use Area)
+ * length.
+ * @returns {Object} An object with {number} `numChars`, {number} `puaLength`,
+ *   and {number} `percentage` parameters.
+ */
+var checkProblematicCharRanges = function checkProblematicCharRanges() {
+  function printRange(limits) {
+    return '[' + limits.lower.toString('16').toUpperCase() + ', ' +
+                  limits.upper.toString('16').toUpperCase() + ')';
+  }
+
+  var numRanges = ProblematicCharRanges.length;
+  if (numRanges % 2 !== 0) {
+    throw new Error('Char ranges must contain an even number of elements.');
+  }
+  var prevLimits, numChars = 0;
+  for (var i = 0; i < numRanges; i += 2) {
+    var limits = {
+      lower: ProblematicCharRanges[i],
+      upper: ProblematicCharRanges[i + 1],
+    };
+    if (!isInt(limits.lower) || !isInt(limits.upper)) {
+      throw new Error('Range endpoints must be integers: ' +
+                      printRange(limits));
+    }
+    if (limits.lower < 0 || limits.upper < 0) {
+      throw new Error('Range endpoints must be non-negative: ' +
+                      printRange(limits));
+    }
+    var range = limits.upper - limits.lower;
+    if (range < 1) {
+      throw new Error('Range must contain at least one element: ' +
+                      printRange(limits));
+    }
+    if (prevLimits) {
+      if (limits.lower < prevLimits.lower) {
+        throw new Error('Ranges must be sorted in ascending order: ' +
+                        printRange(limits) + ', ' + printRange(prevLimits));
+      }
+      if (limits.lower < prevLimits.upper) {
+        throw new Error('Ranges must not overlap: ' +
+                        printRange(limits) + ', ' + printRange(prevLimits));
+      }
+    }
+    prevLimits = {
+      lower: limits.lower,
+      upper: limits.upper,
+    };
+    // The current range is OK.
+    numChars += range;
+  }
+  var puaLength = (PRIVATE_USE_OFFSET_END + 1) - PRIVATE_USE_OFFSET_START;
+  if (numChars > puaLength) {
+    throw new Error('Total number of chars must not exceed the PUA length.');
+  }
+  return {
+    numChars: numChars,
+    puaLength: puaLength,
+    percentage: 100 * (numChars / puaLength),
+  };
+};
 
 describe('Fonts', function() {
   it('checkProblematicCharRanges', function() {