diff --git a/codestyle.md b/codestyle.md
index 1db6ad0f..e40da82e 100644
--- a/codestyle.md
+++ b/codestyle.md
@@ -5,3 +5,4 @@
     otherwise synchronous errors can get swallowed
  - only named exports, no default exports
     otherwise it becomes hard to remember what was a default/named export
+ - should we return promises from storage mutation calls? probably not, as we don't await them anywhere. only read calls should return promises?
diff --git a/package.json b/package.json
index 515ac438..a92949dc 100644
--- a/package.json
+++ b/package.json
@@ -7,7 +7,7 @@
     "doc": "doc"
   },
   "scripts": {
-    "test": "node_modules/.bin/impunity --entry-point src/main.js --force-esm",
+    "test": "node_modules/.bin/impunity --entry-point src/main.js --force-esm-dirs lib/ src/",
     "start": "node scripts/serve-local.js",
     "build": "node --experimental-modules scripts/build.mjs",
     "postinstall": "node ./scripts/post-install.mjs"
@@ -33,7 +33,7 @@
     "commander": "^6.0.0",
     "core-js": "^3.6.5",
     "finalhandler": "^1.1.1",
-    "impunity": "^0.0.12",
+    "impunity": "^1.0.0",
     "mdn-polyfills": "^5.20.0",
     "postcss": "^7.0.32",
     "postcss-css-variables": "^0.17.0",
diff --git a/src/matrix/Session.js b/src/matrix/Session.js
index 503ec3a5..2752fca7 100644
--- a/src/matrix/Session.js
+++ b/src/matrix/Session.js
@@ -301,7 +301,7 @@ export function tests() {
                     }
                 }
             };
-            const newSessionData = session.writeSync("b", 6, {}, syncTxn);
+            const newSessionData = await session.writeSync({next_batch: "b"}, 6, {}, syncTxn);
             assert(syncSet);
             assert.equal(session.syncToken, "a");
             assert.equal(session.syncFilterId, 5);
diff --git a/yarn.lock b/yarn.lock
index a3f1450f..d1bf27a2 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -1002,16 +1002,16 @@ colors@^1.3.3:
   resolved "https://registry.yarnpkg.com/colors/-/colors-1.4.0.tgz#c50491479d4c1bdaed2c9ced32cf7c7dc2360f78"
   integrity sha512-a+UqTh4kgZg/SlGvfbzDHpgRu7AAQOmmqRHJnxhRZICKFUT91brVhNNt58CMWU9PsBbv3PDCZUHbVxuDiH2mtA==
 
-commander@^2.19.0:
-  version "2.20.3"
-  resolved "https://registry.yarnpkg.com/commander/-/commander-2.20.3.tgz#fd485e84c03eb4881c20722ba48035e8531aeb33"
-  integrity sha512-GpVkmM8vF2vQUkj2LvZmD35JxeJOLCwJ9cUkugyk2nuhbv3+mJvpLYYt+0+USMxE+oj+ey/lJEnhZw75x/OMcQ==
-
 commander@^6.0.0:
   version "6.0.0"
   resolved "https://registry.yarnpkg.com/commander/-/commander-6.0.0.tgz#2b270da94f8fb9014455312f829a1129dbf8887e"
   integrity sha512-s7EA+hDtTYNhuXkTlhqew4txMZVdszBmKWSPEMxGr8ru8JXR7bLUFIAtPhcSuFdJQ0ILMxnJi8GkQL0yvDy/YA==
 
+commander@^6.1.0:
+  version "6.1.0"
+  resolved "https://registry.yarnpkg.com/commander/-/commander-6.1.0.tgz#f8d722b78103141006b66f4c7ba1e97315ba75bc"
+  integrity sha512-wl7PNrYWd2y5mp1OK/LhTlv8Ff4kQJQRXXAvF+uU/TPNiVJUxZLRYGj/B0y/lPGAVcSbJqH2Za/cvHmrPMC8mA==
+
 commondir@^1.0.1:
   version "1.0.1"
   resolved "https://registry.yarnpkg.com/commondir/-/commondir-1.0.1.tgz#ddd800da0c66127393cca5950ea968a3aaf1253b"
@@ -1305,13 +1305,13 @@ http-errors@~1.7.2:
     statuses ">= 1.5.0 < 2"
     toidentifier "1.0.0"
 
-impunity@^0.0.12:
-  version "0.0.12"
-  resolved "https://registry.yarnpkg.com/impunity/-/impunity-0.0.12.tgz#cb65316fe04eaf2bbd09ac23430cfdcf8e099ff5"
-  integrity sha512-XID4Ua0CGClVG/dN3jv2lftIIv4orXQ6iGNdqyU8yKKof6+Zp09BEo/XvOIWlRTO90GGINE88f6gx60yPdLvaQ==
+impunity@^1.0.0:
+  version "1.0.0"
+  resolved "https://registry.yarnpkg.com/impunity/-/impunity-1.0.0.tgz#041771ad0563902b3cc55d8adc8c8ea2d501aeb2"
+  integrity sha512-HYvRkcjl1PJKS6ti4M4abG0KT+zobPtm7fx3l6xMjZx/pleKYMH56y7fwy1cIbYbzo9fFFeSJ4H5VF6wBBHB9g==
   dependencies:
     colors "^1.3.3"
-    commander "^2.19.0"
+    commander "^6.1.0"
 
 inflight@^1.0.4:
   version "1.0.6"