diff --git a/src/when.js b/src/when.js
index 70c1e30..760b9bb 100644
--- a/src/when.js
+++ b/src/when.js
@@ -16,6 +16,9 @@ expect.extend({
 })
 expect().__capture_equals__()
 let JEST_MATCHERS_OBJECT = Symbol.for('$$jest-matchers-object')
+// Hackily reset assertionCalls back to zero incase dev's tests are using expect.assertions()
+global[JEST_MATCHERS_OBJECT].state.assertionCalls = 0
+// Hackily delete the custom matcher that we added
 delete global[JEST_MATCHERS_OBJECT].matchers.__capture_equals__
 /**
  * End hack
diff --git a/src/when.test.js b/src/when.test.js
index ea52cd2..1aa506a 100644
--- a/src/when.test.js
+++ b/src/when.test.js
@@ -821,5 +821,9 @@ describe('When', () => {
       expect(fn(1)).toEqual('a') // fails and will still return 'b' (as before my change)
       expect(fn(2)).toEqual('b')
     })
+
+    it('does not add to the number of assertion calls', () => {
+      expect.assertions(0)
+    })
   })
 })