--- a/browser/extensions/formautofill/test/unit/heuristics/third_party/test_BestBuy.js
+++ b/browser/extensions/formautofill/test/unit/heuristics/third_party/test_BestBuy.js
@@ -1,17 +1,17 @@
 /* global runHeuristicsTest */
 
 "use strict";
 
 runHeuristicsTest([
   {
     fixturePath: "Checkout_ShippingAddress.html",
     expectedResult: [
-      [[]], // Search form
+      [], // Search form
       [[
         {"section": "", "addressType": "", "contactType": "", "fieldName": "given-name"},
         {"section": "", "addressType": "", "contactType": "", "fieldName": "family-name"},
         {"section": "", "addressType": "", "contactType": "", "fieldName": "address-line1"},
         {"section": "", "addressType": "", "contactType": "", "fieldName": "address-level2"}, // city
         {"section": "", "addressType": "", "contactType": "", "fieldName": "address-level1"}, // state
         {"section": "", "addressType": "", "contactType": "", "fieldName": "postal-code"},
       ]],
@@ -21,17 +21,17 @@ runHeuristicsTest([
       [[ // unknown
         {"section": "", "addressType": "", "contactType": "", "fieldName": "email"},
         {"section": "", "addressType": "", "contactType": "", "fieldName": "tel"},
       ]],
     ],
   }, {
     fixturePath: "Checkout_Payment.html",
     expectedResult: [
-      [[]], // Search form
+      [], // Search form
       [[ // Sign up
         {"section": "", "addressType": "", "contactType": "", "fieldName": "email"},
       ]],
       [[
         {"section": "", "addressType": "", "contactType": "", "fieldName": "given-name"},
         {"section": "", "addressType": "", "contactType": "", "fieldName": "family-name"},
         {"section": "", "addressType": "", "contactType": "", "fieldName": "address-line1"},
         {"section": "", "addressType": "", "contactType": "", "fieldName": "address-level2"}, // city

--- a/browser/extensions/formautofill/test/unit/heuristics/third_party/test_CDW.js
+++ b/browser/extensions/formautofill/test/unit/heuristics/third_party/test_CDW.js
@@ -15,19 +15,20 @@ runHeuristicsTest([
         {"section": "", "addressType": "", "contactType": "", "fieldName": "address-level2"}, // city
         {"section": "", "addressType": "", "contactType": "", "fieldName": "address-level1"}, // state
         {"section": "", "addressType": "", "contactType": "", "fieldName": "postal-code"},
 
         // FIXME: bug 1392932 - misdetect ZIP ext string
         {"section": "", "addressType": "", "contactType": "", "fieldName": "tel-extension"},
         {"section": "", "addressType": "", "contactType": "", "fieldName": "email"},
         {"section": "", "addressType": "", "contactType": "", "fieldName": "tel"},
+      ], [
         // The below "tel-extension" is correct and removed due to the
         // duplicated field above.
-//      {"section": "", "addressType": "", "contactType": "", "fieldName": "tel-extension"},
+        {"section": "", "addressType": "", "contactType": "", "fieldName": "tel-extension"},
       ]],
       [],
     ],
   }, {
     fixturePath: "Checkout_BillingPaymentInfo.html",
     expectedResult: [
       [[
         {"section": "", "addressType": "", "contactType": "", "fieldName": "given-name"},
@@ -42,21 +43,23 @@ runHeuristicsTest([
         // FIXME: bug 1392932 - misdetect ZIP ext string
         {"section": "", "addressType": "", "contactType": "", "fieldName": "tel-extension"},
 //      {"section": "", "addressType": "", "contactType": "", "fieldName": "cc-type"},
         {"section": "", "addressType": "", "contactType": "", "fieldName": "cc-number"}, // ac-off
         {"section": "", "addressType": "", "contactType": "", "fieldName": "cc-exp-month"},
         {"section": "", "addressType": "", "contactType": "", "fieldName": "cc-exp-year"},
 
 //      {"section": "", "addressType": "", "contactType": "", "fieldName": "cc-csc"},
+      ], [
+        {"section": "", "addressType": "", "contactType": "", "fieldName": "tel-extension"},
       ]],
       [],
     ],
   }, {
     fixturePath: "Checkout_Logon.html",
     expectedResult: [
       [],
-      [[]],
+      [],
       [],
     ],
   },
 ], "../../../fixtures/third_party/CDW/");
 

--- a/browser/extensions/formautofill/test/unit/heuristics/third_party/test_CostCo.js
+++ b/browser/extensions/formautofill/test/unit/heuristics/third_party/test_CostCo.js
@@ -45,25 +45,24 @@ runHeuristicsTest([
   }, {
     fixturePath: "Payment.html",
     expectedResult: [
       [[
 //      {"section": "", "addressType": "", "contactType": "", "fieldName": "cc-type"},
         {"section": "", "addressType": "", "contactType": "", "fieldName": "cc-number"}, // ac-off
         {"section": "", "addressType": "", "contactType": "", "fieldName": "cc-exp-month"},
         {"section": "", "addressType": "", "contactType": "", "fieldName": "cc-exp-year"},
-
 //      {"section": "", "addressType": "", "contactType": "", "fieldName": "cc-csc"}, // ac-off
         {"section": "", "addressType": "", "contactType": "", "fieldName": "cc-name"}, // ac-off
       ]],
       [[
         {"section": "", "addressType": "", "contactType": "", "fieldName": "cc-number"}, // ac-off
       ]],
       [],
-      [[]],
+      [],
       [[
         {"section": "", "addressType": "", "contactType": "", "fieldName": "given-name"},
         {"section": "", "addressType": "", "contactType": "", "fieldName": "additional-name"}, // middle-name initial
         {"section": "", "addressType": "", "contactType": "", "fieldName": "family-name"},
         {"section": "", "addressType": "", "contactType": "", "fieldName": "organization"},
         {"section": "", "addressType": "", "contactType": "", "fieldName": "country"},
         {"section": "", "addressType": "", "contactType": "", "fieldName": "address-line1"},
         {"section": "", "addressType": "", "contactType": "", "fieldName": "address-line2"},
@@ -91,17 +90,17 @@ runHeuristicsTest([
       [[
         {"section": "", "addressType": "", "contactType": "", "fieldName": "email"},
       ]],
       [],
     ],
   }, {
     fixturePath: "SignIn.html",
     expectedResult: [
-      [[]],
+      [],
       [],
       [[
         {"section": "", "addressType": "", "contactType": "", "fieldName": "email"},
       ]],
       [],
       [[ // Forgot password
         {"section": "", "addressType": "", "contactType": "", "fieldName": "email"},
       ]],

--- a/browser/extensions/formautofill/test/unit/heuristics/third_party/test_Macys.js
+++ b/browser/extensions/formautofill/test/unit/heuristics/third_party/test_Macys.js
@@ -11,20 +11,17 @@ runHeuristicsTest([
         {"section": "", "addressType": "", "contactType": "", "fieldName": "family-name"},
         {"section": "", "addressType": "", "contactType": "", "fieldName": "address-line1"},
         {"section": "", "addressType": "", "contactType": "", "fieldName": "address-line2"},
         {"section": "", "addressType": "", "contactType": "", "fieldName": "address-level2"}, // city
         {"section": "", "addressType": "", "contactType": "", "fieldName": "address-level1"}, // state
         {"section": "", "addressType": "", "contactType": "", "fieldName": "postal-code"},
         {"section": "", "addressType": "", "contactType": "", "fieldName": "tel"},
       ]],
-      [
-/*
-*/
-      ],
+      [],
     ],
   }, {
     fixturePath: "Checkout_Payment.html",
     expectedResult: [
       [[
 //      {"section": "", "addressType": "", "contactType": "", "fieldName": "cc-type"}, // ac-off
         {"section": "", "addressType": "", "contactType": "", "fieldName": "cc-number"}, // ac-off
         {"section": "", "addressType": "", "contactType": "", "fieldName": "cc-exp-month"}, // ac-off
@@ -51,15 +48,15 @@ runHeuristicsTest([
 //      {"section": "", "addressType": "", "contactType": "", "fieldName": "password"},
       ]],
       [[ // Forgot password
         {"section": "", "addressType": "", "contactType": "", "fieldName": "email"},
       ]],
       [[
         {"section": "", "addressType": "", "contactType": "", "fieldName": "email"},
       ]],
-      [[]],
+      [],
       [],
       [],
     ],
   },
 ], "../../../fixtures/third_party/Macys/");
 

--- a/browser/extensions/formautofill/test/unit/heuristics/third_party/test_NewEgg.js
+++ b/browser/extensions/formautofill/test/unit/heuristics/third_party/test_NewEgg.js
@@ -21,16 +21,19 @@ runHeuristicsTest([
       [],
     ],
   }, {
     fixturePath: "BillingInfo.html",
     expectedResult: [
       [[
         {"section": "", "addressType": "", "contactType": "", "fieldName": "cc-name"},
         {"section": "", "addressType": "", "contactType": "", "fieldName": "cc-number"}, // ac-off
+      ], [
+        {"section": "", "addressType": "", "contactType": "", "fieldName": "cc-name"},
+        {"section": "", "addressType": "", "contactType": "", "fieldName": "cc-number"}, // ac-off
         {"section": "", "addressType": "", "contactType": "", "fieldName": "cc-exp-month"},
         {"section": "", "addressType": "", "contactType": "", "fieldName": "cc-exp-year"},
 //      {"section": "", "addressType": "", "contactType": "", "fieldName": "cc-csc"},
         {"section": "", "addressType": "", "contactType": "", "fieldName": "country"},
         {"section": "", "addressType": "", "contactType": "", "fieldName": "address-line1"},
         {"section": "", "addressType": "", "contactType": "", "fieldName": "address-line2"},
         {"section": "", "addressType": "", "contactType": "", "fieldName": "address-level2"},
         {"section": "", "addressType": "", "contactType": "", "fieldName": "address-level1"}, // state

--- a/browser/extensions/formautofill/test/unit/heuristics/third_party/test_OfficeDepot.js
+++ b/browser/extensions/formautofill/test/unit/heuristics/third_party/test_OfficeDepot.js
@@ -50,15 +50,15 @@ runHeuristicsTest([
         // FIXME: bug 1392950 - the membership number should not be detected
         // as cc-number.
         {"section": "", "addressType": "", "contactType": "", "fieldName": "cc-number"},
       ]],
     ],
   }, {
     fixturePath: "SignIn.html",
     expectedResult: [
-      [[ // ac-off
+      [ // ac-off
 //      {"section": "", "addressType": "", "contactType": "", "fieldName": "email"},
-      ]],
+      ],
     ],
   },
 ], "../../../fixtures/third_party/OfficeDepot/");
 

--- a/browser/extensions/formautofill/test/unit/heuristics/third_party/test_QVC.js
+++ b/browser/extensions/formautofill/test/unit/heuristics/third_party/test_QVC.js
@@ -8,50 +8,50 @@ runHeuristicsTest([
     expectedResult: [
       [[
 //      {"section": "", "addressType": "", "contactType": "", "fieldName": "tel"}, // ac-off
         {"section": "", "addressType": "", "contactType": "", "fieldName": "email"},
 //      {"section": "", "addressType": "", "contactType": "", "fieldName": "bday-month"}, // select
 //      {"section": "", "addressType": "", "contactType": "", "fieldName": "bday-day"}, // select
 //      {"section": "", "addressType": "", "contactType": "", "fieldName": "bday-year"},
 //      {"section": "", "addressType": "", "contactType": "", "fieldName": "cc-type"},
-
         {"section": "", "addressType": "", "contactType": "", "fieldName": "cc-number"},
         {"section": "", "addressType": "", "contactType": "", "fieldName": "cc-exp"},
-
 //      {"section": "", "addressType": "", "contactType": "", "fieldName": "cc-csc"},
+      ], [
+        {"section": "", "addressType": "", "contactType": "", "fieldName": "cc-number"},
       ]],
       [[
         {"section": "", "addressType": "", "contactType": "", "fieldName": "email"},
       ]],
     ],
   }, {
     fixturePath: "PaymentMethod.html",
     expectedResult: [
       [[
 //      {"section": "", "addressType": "", "contactType": "", "fieldName": "tel"}, // ac-off
         {"section": "", "addressType": "", "contactType": "", "fieldName": "email"},
 //      {"section": "", "addressType": "", "contactType": "", "fieldName": "bday-month"}, // select
 //      {"section": "", "addressType": "", "contactType": "", "fieldName": "bday-day"}, // select
 //      {"section": "", "addressType": "", "contactType": "", "fieldName": "bday-year"}, // select
 //      {"section": "", "addressType": "", "contactType": "", "fieldName": "cc-type"}, // select
-
         {"section": "", "addressType": "", "contactType": "", "fieldName": "cc-number"}, // ac-off
         {"section": "", "addressType": "", "contactType": "", "fieldName": "cc-exp"},
-
 //      {"section": "", "addressType": "", "contactType": "", "fieldName": "cc-csc"},
+      ], [
+        {"section": "", "addressType": "", "contactType": "", "fieldName": "cc-number"}, // ac-off
       ]],
       [[
         {"section": "", "addressType": "", "contactType": "", "fieldName": "email"},
       ]],
     ],
   }, {
     fixturePath: "SignIn.html",
     expectedResult: [
-      [[]],
+      [],
       [[ // Sign in
         {"section": "", "addressType": "", "contactType": "", "fieldName": "email"},
       ]],
       [],
     ],
   },
 ], "../../../fixtures/third_party/QVC/");
 

--- a/browser/extensions/formautofill/test/unit/heuristics/third_party/test_Sears.js
+++ b/browser/extensions/formautofill/test/unit/heuristics/third_party/test_Sears.js
@@ -2,61 +2,61 @@
 
 "use strict";
 
 runHeuristicsTest([
   {
     fixturePath: "ShippingAddress.html",
     expectedResult: [
       [],
-      [[]], // search form, ac-off
-      [[ // ac-off
+      [], // search form, ac-off
+      [ // ac-off
 //      {"section": "", "addressType": "", "contactType": "", "fieldName": "email"},
-      ]],
-      [[ // check-out, ac-off
+      ],
+      [ // check-out, ac-off
 /*
         {"section": "", "addressType": "", "contactType": "", "fieldName": "given-name"},
         {"section": "", "addressType": "", "contactType": "", "fieldName": "family-name"},
         {"section": "", "addressType": "", "contactType": "", "fieldName": "address-line1"},
         {"section": "", "addressType": "", "contactType": "", "fieldName": "address-line2"},
         {"section": "", "addressType": "", "contactType": "", "fieldName": "address-level2"},
         {"section": "", "addressType": "", "contactType": "", "fieldName": "address-level1"},
         {"section": "", "addressType": "", "contactType": "", "fieldName": "postal-code"},
         {"section": "", "addressType": "", "contactType": "", "fieldName": "tel"},
 //      {"section": "", "addressType": "", "contactType": "", "fieldName": "tel-extension"},
         {"section": "", "addressType": "", "contactType": "", "fieldName": "email"},
 */
-      ]],
+      ],
       [ // ac-off
 /*
         {"section": "", "addressType": "", "contactType": "", "fieldName": "email"},
         {"section": "", "addressType": "", "contactType": "", "fieldName": "given-name"},
         {"section": "", "addressType": "", "contactType": "", "fieldName": "family-name"},
         {"section": "", "addressType": "", "contactType": "", "fieldName": "address-line1"},
         {"section": "", "addressType": "", "contactType": "", "fieldName": "address-line2"},
         {"section": "", "addressType": "", "contactType": "", "fieldName": "address-level2"},
         {"section": "", "addressType": "", "contactType": "", "fieldName": "address-level1"},
         {"section": "", "addressType": "", "contactType": "", "fieldName": "postal-code"},
         {"section": "", "addressType": "", "contactType": "", "fieldName": "tel"},
         {"section": "", "addressType": "", "contactType": "", "fieldName": "tel-extension"},
 //      {"section": "", "addressType": "", "contactType": "", "fieldName": "new-password"},
 */
       ],
-      [[ // ac-off
+      [ // ac-off
 //      {"section": "", "addressType": "", "contactType": "", "fieldName": "email"},
-      ]],
-      [[ // ac-off
+      ],
+      [ // ac-off
 //      {"section": "", "addressType": "", "contactType": "", "fieldName": "email"},
-      ]],
+      ],
     ],
   }, {
     fixturePath: "PaymentOptions.html",
     expectedResult: [
       [],
-      [[]], // search
+      [], // search
       [[ // credit card
         {"section": "", "addressType": "", "contactType": "", "fieldName": "cc-number"},
         // FIXME: bug 1392958 - Cardholder name field should be detected as cc-name
 //      {"section": "", "addressType": "", "contactType": "", "fieldName": "cc-name"},
 //      {"section": "", "addressType": "", "contactType": "", "fieldName": "cc-csc"},
         {"section": "", "addressType": "", "contactType": "", "fieldName": "cc-exp-month"},
         {"section": "", "addressType": "", "contactType": "", "fieldName": "cc-exp-year"},
       ]],

--- a/browser/extensions/formautofill/test/unit/heuristics/third_party/test_Staples.js
+++ b/browser/extensions/formautofill/test/unit/heuristics/third_party/test_Staples.js
@@ -1,25 +1,25 @@
 /* global runHeuristicsTest */
 
 "use strict";
 
 runHeuristicsTest([
   {
     fixturePath: "Basic.html",
     expectedResult: [
-      [[ // ac-off
+      [ // ac-off
 //      {"section": "", "addressType": "", "contactType": "", "fieldName": "given-name"},
 //      {"section": "", "addressType": "", "contactType": "", "fieldName": "family-name"},
 //      {"section": "", "addressType": "", "contactType": "", "fieldName": "address-line1"},
 //      {"section": "", "addressType": "", "contactType": "", "fieldName": "email"},
 //      {"section": "", "addressType": "", "contactType": "", "fieldName": "tel"},
 //      {"section": "", "addressType": "", "contactType": "", "fieldName": "tel-extension"},
 //      {"section": "", "addressType": "", "contactType": "", "fieldName": "organization"},
-      ]],
+      ],
     ],
   }, {
     fixturePath: "Basic_ac_on.html",
     expectedResult: [
       [[
         {"section": "", "addressType": "", "contactType": "", "fieldName": "given-name"},
         {"section": "", "addressType": "", "contactType": "", "fieldName": "family-name"},
         {"section": "", "addressType": "", "contactType": "", "fieldName": "address-line1"},

--- a/browser/extensions/formautofill/test/unit/heuristics/third_party/test_Walmart.js
+++ b/browser/extensions/formautofill/test/unit/heuristics/third_party/test_Walmart.js
@@ -4,33 +4,33 @@
 
 runHeuristicsTest([
   {
     fixturePath: "Checkout.html",
     expectedResult: [
       [[
         {"section": "", "addressType": "", "contactType": "", "fieldName": "postal-code"},
       ]],
-      [[]],
+      [],
       [[
         {"section": "", "addressType": "", "contactType": "", "fieldName": "email"},
 //      {"section": "", "addressType": "", "contactType": "", "fieldName": "password"}, // ac-off
       ]],
       [[
         {"section": "", "addressType": "", "contactType": "", "fieldName": "given-name"},
         {"section": "", "addressType": "", "contactType": "", "fieldName": "family-name"},
 //      {"section": "", "addressType": "", "contactType": "", "fieldName": "email"}, // ac-off
 //      {"section": "", "addressType": "", "contactType": "", "fieldName": "password"},
 //      {"section": "", "addressType": "", "contactType": "", "fieldName": "password"}, // ac-off
       ]],
     ],
   }, {
     fixturePath: "Payment.html",
     expectedResult: [
-      [[]],
+      [],
       [
         [
           {"section": "section-payment", "addressType": "", "contactType": "", "fieldName": "given-name"},
           {"section": "section-payment", "addressType": "", "contactType": "", "fieldName": "family-name"},
           {"section": "section-payment", "addressType": "", "contactType": "", "fieldName": "cc-number"},
           {"section": "section-payment", "addressType": "", "contactType": "", "fieldName": "cc-exp-month"},
           {"section": "section-payment", "addressType": "", "contactType": "", "fieldName": "cc-exp-year"},
 //        {"section": "section-payment", "addressType": "", "contactType": "", "fieldName": "cc-csc"},
@@ -45,17 +45,17 @@ runHeuristicsTest([
       ],
     ],
   }, {
     fixturePath: "Shipping.html",
     expectedResult: [
       [[
         {"section": "", "addressType": "", "contactType": "", "fieldName": "postal-code"},
       ]],
-      [[]],
+      [],
       [[
         {"section": "", "addressType": "", "contactType": "", "fieldName": "given-name"},
         {"section": "", "addressType": "", "contactType": "", "fieldName": "family-name"},
         {"section": "", "addressType": "", "contactType": "", "fieldName": "tel"},
         {"section": "", "addressType": "", "contactType": "", "fieldName": "address-line1"},
         {"section": "", "addressType": "", "contactType": "", "fieldName": "address-line2"},
         {"section": "", "addressType": "", "contactType": "", "fieldName": "address-level2"}, // city
         {"section": "", "addressType": "", "contactType": "", "fieldName": "address-level1"}, // state

--- a/browser/extensions/formautofill/test/unit/test_collectFormFields.js
+++ b/browser/extensions/formautofill/test/unit/test_collectFormFields.js
@@ -287,20 +287,32 @@ const TESTCASES = [
                </form>`,
     allowDuplicates: true,
     sections: [{
       addressFieldDetails: [
         {"section": "", "addressType": "", "contactType": "", "fieldName": "tel-area-code"},
         {"section": "", "addressType": "", "contactType": "", "fieldName": "tel-local-prefix"},
         {"section": "", "addressType": "", "contactType": "", "fieldName": "tel-local-suffix"},
         {"section": "", "addressType": "", "contactType": "", "fieldName": "tel-extension"},
+      ],
+      creditCardFieldDetails: [],
+    }, {
+      addressFieldDetails: [
         {"section": "", "addressType": "", "contactType": "", "fieldName": "tel-area-code"},
         {"section": "", "addressType": "", "contactType": "", "fieldName": "tel-local-prefix"},
         {"section": "", "addressType": "", "contactType": "", "fieldName": "tel-local-suffix"},
+
+        // TODO Bug 1421181 - "tel-country-code" field should belong to the next
+        // section. There should be a way to group the related fields during the
+        // parsing stage.
         {"section": "", "addressType": "", "contactType": "", "fieldName": "tel-country-code"},
+      ],
+      creditCardFieldDetails: [],
+    }, {
+      addressFieldDetails: [
         {"section": "", "addressType": "", "contactType": "", "fieldName": "tel-area-code"},
         {"section": "", "addressType": "", "contactType": "", "fieldName": "tel-local-prefix"},
         {"section": "", "addressType": "", "contactType": "", "fieldName": "tel-local-suffix"},
       ],
       creditCardFieldDetails: [],
     }],
     validFieldDetails: [
       {"section": "", "addressType": "", "contactType": "", "fieldName": "tel-area-code"},
@@ -456,23 +468,20 @@ for (let tc of TESTCASES) {
         handlerDetails.forEach((detail, index) => {
           Assert.equal(detail.fieldName, testCaseDetails[index].fieldName, "fieldName");
           Assert.equal(detail.section, testCaseDetails[index].section, "section");
           Assert.equal(detail.addressType, testCaseDetails[index].addressType, "addressType");
           Assert.equal(detail.contactType, testCaseDetails[index].contactType, "contactType");
           Assert.equal(detail.elementWeakRef.get(), testCaseDetails[index].elementWeakRef.get(), "DOM reference");
         });
       }
-      for (let i = 0; i < testcase.sections.length; i++) {
-        let section = testcase.sections[i];
-        [
-          section.addressFieldDetails,
-          section.creditCardFieldDetails,
-        ].forEach(details => setElementWeakRef(details));
-      }
+      setElementWeakRef(testcase.sections.reduce((fieldDetails, section) => {
+        fieldDetails.push(...section.addressFieldDetails, ...section.creditCardFieldDetails);
+        return fieldDetails;
+      }, []));
       setElementWeakRef(testcase.validFieldDetails);
 
       let handler = new FormAutofillHandler(formLike);
       let validFieldDetails = handler.collectFormFields(testcase.allowDuplicates);
 
       Assert.equal(handler.sections.length, testcase.sections.length);
       for (let i = 0; i < handler.sections.length; i++) {
         let section = handler.sections[i];