diff --git a/mobile/android/geckoview/src/androidTest/java/org/mozilla/geckoview/test/rule/GeckoSessionTestRule.java b/mobile/android/geckoview/src/androidTest/java/org/mozilla/geckoview/test/rule/GeckoSessionTestRule.java
index ca3a54215d12..b174c9e7ee33 100644
--- a/mobile/android/geckoview/src/androidTest/java/org/mozilla/geckoview/test/rule/GeckoSessionTestRule.java
+++ b/mobile/android/geckoview/src/androidTest/java/org/mozilla/geckoview/test/rule/GeckoSessionTestRule.java
@@ -226,15 +226,16 @@ public class GeckoSessionTestRule extends UiThreadTestRule {
     @Retention(RetentionPolicy.RUNTIME)
     public @interface AssertCalled {
         /**
-         * @return True if the method must be called,
+         * @return True if the method must be called if count != 0,
          *         or false if the method must not be called.
          */
         boolean value() default true;
 
         /**
-         * @return If called, the number of calls called, or 0 to allow any number > 0.
+         * @return The number of calls allowed. Specify -1 to allow any number > 0. Specify 0 to
+         *         assert the method is not called, even if value() is true.
          */
-        int count() default 0;
+        int count() default -1;
 
         /**
          * @return If called, the order number for each call, or 0 to allow arbitrary
@@ -325,8 +326,8 @@ public class GeckoSessionTestRule extends UiThreadTestRule {
         }
 
         /* package */ int getCount() {
-            return (requirement == null) ? 0 :
-                   !requirement.allowed ? -1 : requirement.count;
+            return (requirement == null) ? -1 :
+                   requirement.allowed ? requirement.count : 0;
         }
 
         /* package */ void incrementCounter() {
@@ -338,12 +339,12 @@ public class GeckoSessionTestRule extends UiThreadTestRule {
         }
 
         /* package */ boolean allowUnlimitedCalls() {
-            return getCount() == 0;
+            return getCount() == -1;
         }
 
         /* package */ boolean allowMoreCalls() {
             final int count = getCount();
-            return count == 0 || count > currentCount;
+            return count == -1 || count > currentCount;
         }
 
         /* package */ CallInfo getInfo() {
@@ -569,9 +570,9 @@ public class GeckoSessionTestRule extends UiThreadTestRule {
 
     private void assertAllowMoreCalls(final MethodCall call) {
         final int count = call.getCount();
-        if (count != 0) {
+        if (count != -1) {
             assertThat(call.method.getName() + " call count should be within limit",
-                       call.getCurrentCount() + 1, lessThanOrEqualTo(Math.max(0, count)));
+                       call.getCurrentCount() + 1, lessThanOrEqualTo(count));
         }
     }
 
@@ -588,10 +589,10 @@ public class GeckoSessionTestRule extends UiThreadTestRule {
             return;
         }
         final int count = call.getCount();
-        if (count < 0) {
+        if (count == 0) {
             assertThat(call.method.getName() + " should not be called",
                        call.getCurrentCount(), equalTo(0));
-        } else if (count == 0) {
+        } else if (count == -1) {
             assertThat(call.method.getName() + " should be called",
                        call.getCurrentCount(), greaterThan(0));
         } else {