diff --git a/src/observer.ts b/src/observer.ts
new file mode 100644
index 00000000..c1afc939
--- /dev/null
+++ b/src/observer.ts
@@ -0,0 +1,142 @@
+//------------------------------------------------------------------------------
+// Observer
+//------------------------------------------------------------------------------
+export interface Observer {
+  rev: number;
+  allowMutations: boolean;
+  observe: (val: any) => void;
+  set: (target: any, key: number | string, value: any) => void;
+}
+
+export function makeObserver(): Observer {
+  const observer: Observer = {
+    rev: 1,
+    allowMutations: true,
+    observe: observe,
+    set: set
+  };
+
+  function set(target: any, key: number | string, value: any) {
+    addProp(target, key, value);
+    target.__owl__.rev++;
+    observer.rev++;
+  }
+
+  function addProp<T extends { __owl__?: any }>(
+    obj: T,
+    key: string | number,
+    value: any
+  ) {
+    Object.defineProperty(obj, key, {
+      enumerable: true,
+      get() {
+        return value;
+      },
+      set(newVal) {
+        if (!observer.allowMutations) {
+          throw new Error(
+            `State cannot be changed outside a mutation! (key: "${key}", val: "${newVal}")`
+          );
+        }
+        if (newVal !== value) {
+          unobserve(value);
+          value = newVal;
+          observe(newVal, obj);
+          obj.__owl__.rev!++;
+          observer.rev++;
+          let parent = obj;
+          do {
+            parent.__owl__.deepRev++;
+          } while ((parent = parent.__owl__.parent));
+        }
+      }
+    });
+    observe(value, obj);
+  }
+
+  function observeObj<T extends { __owl__?: any }>(obj: T, parent?: any) {
+    const keys = Object.keys(obj);
+    obj.__owl__ = { rev: 1, deepRev: 1, parent };
+    Object.defineProperty(obj, "__owl__", { enumerable: false });
+    for (let key of keys) {
+      addProp(obj, key, obj[key]);
+    }
+  }
+
+  const ArrayProto = Array.prototype;
+  const ModifiedArrayProto = Object.create(ArrayProto);
+
+  const methodsToPatch = [
+    "push",
+    "pop",
+    "shift",
+    "unshift",
+    "splice",
+    "sort",
+    "reverse"
+  ];
+
+  for (let method of methodsToPatch) {
+    const initialMethod = ArrayProto[method];
+    ModifiedArrayProto[method] = function(...args) {
+      observer.rev++;
+      this.__owl__.rev++;
+      let parent = this;
+      do {
+        parent.__owl__.deepRev++;
+      } while ((parent = parent.__owl__.parent));
+      let inserted;
+      switch (method) {
+        case "push":
+        case "unshift":
+          inserted = args;
+          break;
+        case "splice":
+          inserted = args.slice(2);
+          break;
+      }
+      if (inserted) {
+        for (let elem of inserted) {
+          observe(elem, this);
+        }
+      }
+      return initialMethod.call(this, ...args);
+    };
+  }
+
+  function observeArr(arr: Array<any>, parent?: any) {
+    (<any>arr).__owl__ = { rev: 1, deepRev: 1, parent };
+    Object.defineProperty(arr, "__owl__", { enumerable: false });
+    (<any>arr).__proto__ = ModifiedArrayProto;
+    for (let i = 0; i < arr.length; i++) {
+      observe(arr[i], arr);
+    }
+  }
+
+  function observe(value: any, parent?: any) {
+    if (value === null) {
+      // fun fact: typeof null === 'object'
+      return;
+    }
+    if (typeof value !== "object") {
+      return;
+    }
+    if ("__owl__" in value) {
+      // already observed
+      return;
+    }
+    if (Array.isArray(value)) {
+      observeArr(value, parent);
+    } else {
+      observeObj(value, parent);
+    }
+  }
+
+  function unobserve(target: any) {
+    if (target !== null && typeof target === "object") {
+      delete target.__owl__;
+    }
+  }
+
+  return observer;
+}
diff --git a/src/store.ts b/src/store.ts
index 738bbe3b..fabd409c 100644
--- a/src/store.ts
+++ b/src/store.ts
@@ -1,5 +1,6 @@
 import { Component } from "./component";
 import { EventBus } from "./event_bus";
+import { makeObserver, Observer } from "./observer";
 
 //------------------------------------------------------------------------------
 // Store Definition
@@ -106,149 +107,6 @@ export class Store extends EventBus {
   }
 }
 
-//------------------------------------------------------------------------------
-// Observer
-//------------------------------------------------------------------------------
-interface Observer {
-  rev: number;
-  allowMutations: boolean;
-  observe: (val: any) => void;
-  set: (target: any, key: number | string, value: any) => void;
-}
-
-export function makeObserver(): Observer {
-  const observer: Observer = {
-    rev: 1,
-    allowMutations: true,
-    observe: observe,
-    set: set
-  };
-
-  function set(target: any, key: number | string, value: any) {
-    addProp(target, key, value);
-    target.__owl__.rev++;
-    observer.rev++;
-  }
-
-  function addProp<T extends { __owl__?: any }>(
-    obj: T,
-    key: string | number,
-    value: any
-  ) {
-    Object.defineProperty(obj, key, {
-      enumerable: true,
-      get() {
-        return value;
-      },
-      set(newVal) {
-        if (!observer.allowMutations) {
-          throw new Error(
-            `State cannot be changed outside a mutation! (key: "${key}", val: "${newVal}")`
-          );
-        }
-        if (newVal !== value) {
-          unobserve(value);
-          value = newVal;
-          observe(newVal, obj);
-          obj.__owl__.rev!++;
-          observer.rev++;
-          let parent = obj;
-          do {
-            parent.__owl__.deepRev++;
-          } while ((parent = parent.__owl__.parent));
-        }
-      }
-    });
-    observe(value, obj);
-  }
-
-  function observeObj<T extends { __owl__?: any }>(obj: T, parent?: any) {
-    const keys = Object.keys(obj);
-    obj.__owl__ = { rev: 1, deepRev: 1, parent };
-    Object.defineProperty(obj, "__owl__", { enumerable: false });
-    for (let key of keys) {
-      addProp(obj, key, obj[key]);
-    }
-  }
-
-  const ArrayProto = Array.prototype;
-  const ModifiedArrayProto = Object.create(ArrayProto);
-
-  const methodsToPatch = [
-    "push",
-    "pop",
-    "shift",
-    "unshift",
-    "splice",
-    "sort",
-    "reverse"
-  ];
-
-  for (let method of methodsToPatch) {
-    const initialMethod = ArrayProto[method];
-    ModifiedArrayProto[method] = function(...args) {
-      observer.rev++;
-      this.__owl__.rev++;
-      let parent = this;
-      do {
-        parent.__owl__.deepRev++;
-      } while ((parent = parent.__owl__.parent));
-      let inserted;
-      switch (method) {
-        case "push":
-        case "unshift":
-          inserted = args;
-          break;
-        case "splice":
-          inserted = args.slice(2);
-          break;
-      }
-      if (inserted) {
-        for (let elem of inserted) {
-          observe(elem, this);
-        }
-      }
-      return initialMethod.call(this, ...args);
-    };
-  }
-
-  function observeArr(arr: Array<any>, parent?: any) {
-    (<any>arr).__owl__ = { rev: 1, deepRev: 1, parent };
-    Object.defineProperty(arr, "__owl__", { enumerable: false });
-    (<any>arr).__proto__ = ModifiedArrayProto;
-    for (let i = 0; i < arr.length; i++) {
-      observe(arr[i], arr);
-    }
-  }
-
-  function observe(value: any, parent?: any) {
-    if (value === null) {
-      // fun fact: typeof null === 'object'
-      return;
-    }
-    if (typeof value !== "object") {
-      return;
-    }
-    if ("__owl__" in value) {
-      // already observed
-      return;
-    }
-    if (Array.isArray(value)) {
-      observeArr(value, parent);
-    } else {
-      observeObj(value, parent);
-    }
-  }
-
-  function unobserve(target: any) {
-    if (target !== null && typeof target === "object") {
-      delete target.__owl__;
-    }
-  }
-
-  return observer;
-}
-
 //------------------------------------------------------------------------------
 // Connect function
 //------------------------------------------------------------------------------
diff --git a/tests/observer.test.ts b/tests/observer.test.ts
new file mode 100644
index 00000000..f4d80932
--- /dev/null
+++ b/tests/observer.test.ts
@@ -0,0 +1,255 @@
+import { makeObserver } from "../src/observer";
+
+describe("observer", () => {
+  test("properly observe objects", () => {
+    const observer = makeObserver();
+    const obj: any = {};
+
+    observer.observe(obj);
+    expect(obj.__owl__.rev).toBe(1);
+    expect(observer.rev).toBe(1);
+
+    const ob2: any = { a: 1 };
+    observer.observe(ob2);
+    expect(ob2.__owl__.rev).toBe(1);
+    ob2.a = 2;
+    expect(observer.rev).toBe(2);
+    expect(ob2.__owl__.rev).toBe(2);
+
+    ob2.b = 3;
+    expect(observer.rev).toBe(2);
+    expect(ob2.__owl__.rev).toBe(2);
+
+    observer.set(ob2, "b", 4);
+    expect(observer.rev).toBe(3);
+    expect(ob2.__owl__.rev).toBe(3);
+  });
+
+  test("properly handle null or undefined", () => {
+    const observer = makeObserver();
+    const obj: any = { a: null, b: undefined };
+
+    observer.observe(obj);
+    expect(obj.__owl__.rev).toBe(1);
+    expect(observer.rev).toBe(1);
+
+    obj.a = 3;
+    expect(obj.__owl__.rev).toBe(2);
+
+    obj.b = 5;
+    expect(obj.__owl__.rev).toBe(3);
+
+    obj.a = null;
+    obj.b = undefined;
+    expect(obj.__owl__.rev).toBe(5);
+  });
+
+  test("can change values in array", () => {
+    const observer = makeObserver();
+    const obj: any = { arr: [1, 2] };
+
+    observer.observe(obj);
+    expect(obj.arr.__owl__.rev).toBe(1);
+    expect(observer.rev).toBe(1);
+
+    obj.arr[0] = "nope";
+    expect(obj.arr.__owl__.rev).toBe(1);
+    expect(observer.rev).toBe(1);
+
+    observer.set(obj.arr, 0, "yep");
+    expect(obj.arr.__owl__.rev).toBe(2);
+    expect(observer.rev).toBe(2);
+  });
+
+  test("various object property changes", () => {
+    const observer = makeObserver();
+    const obj: any = { a: 1 };
+    observer.observe(obj);
+    expect(obj.__owl__.rev).toBe(1);
+    obj.a = 2;
+    expect(observer.rev).toBe(2);
+    expect(obj.__owl__.rev).toBe(2);
+
+    // same value again
+    obj.a = 2;
+    expect(observer.rev).toBe(2);
+    expect(obj.__owl__.rev).toBe(2);
+
+    obj.a = 3;
+    expect(observer.rev).toBe(3);
+    expect(obj.__owl__.rev).toBe(3);
+  });
+
+  test("properly observe arrays", () => {
+    const observer = makeObserver();
+    const arr: any = [];
+    observer.observe(arr);
+    expect(arr.__owl__.rev).toBe(1);
+    expect(observer.rev).toBe(1);
+    expect(arr.length).toBe(0);
+
+    arr.push(1);
+    expect(arr.__owl__.rev).toBe(2);
+    expect(observer.rev).toBe(2);
+    expect(arr.length).toBe(1);
+
+    arr.splice(1, 0, "hey");
+    expect(arr.__owl__.rev).toBe(3);
+    expect(observer.rev).toBe(3);
+    expect(arr.length).toBe(2);
+
+    arr.unshift("lindemans");
+    expect(arr.__owl__.rev).toBe(4);
+
+    arr.reverse();
+    expect(arr.__owl__.rev).toBe(5);
+
+    arr.pop();
+    expect(arr.__owl__.rev).toBe(6);
+
+    arr.shift();
+    expect(arr.__owl__.rev).toBe(7);
+
+    arr.sort();
+    expect(arr.__owl__.rev).toBe(8);
+
+    expect(arr).toEqual([1]);
+  });
+
+  test("object pushed into arrays are observed", () => {
+    const observer = makeObserver();
+    const arr: any = [];
+    observer.observe(arr);
+    expect(observer.rev).toBe(1);
+
+    arr.push({ kriek: 5 });
+    expect(observer.rev).toBe(2);
+    expect(arr.__owl__.rev).toBe(2);
+    expect(arr[0].__owl__.rev).toBe(1);
+
+    arr[0].kriek = 6;
+    expect(observer.rev).toBe(3);
+    expect(arr.__owl__.rev).toBe(2);
+    expect(arr[0].__owl__.rev).toBe(2);
+  });
+
+  test("properly observe arrays in object", () => {
+    const observer = makeObserver();
+    const state: any = { arr: [] };
+    observer.observe(state);
+    expect(state.arr.__owl__.rev).toBe(1);
+    expect(observer.rev).toBe(1);
+    expect(state.arr.length).toBe(0);
+
+    state.arr.push(1);
+    expect(state.arr.__owl__.rev).toBe(2);
+    expect(observer.rev).toBe(2);
+    expect(state.arr.length).toBe(1);
+  });
+
+  test("properly observe objects in array", () => {
+    const observer = makeObserver();
+    const state: any = { arr: [{ something: 1 }] };
+    observer.observe(state);
+    expect(state.arr.__owl__.rev).toBe(1);
+    expect(state.arr[0].__owl__.rev).toBe(1);
+
+    state.arr[0].something = 2;
+    expect(state.arr.__owl__.rev).toBe(1);
+    expect(state.arr[0].__owl__.rev).toBe(2);
+  });
+
+  test("properly observe objects in object", () => {
+    const observer = makeObserver();
+    const state: any = { a: { b: 1 } };
+    observer.observe(state);
+    expect(state.__owl__.rev).toBe(1);
+    expect(state.a.__owl__.rev).toBe(1);
+
+    state.a.b = 2;
+    expect(state.__owl__.rev).toBe(1);
+    expect(state.a.__owl__.rev).toBe(2);
+  });
+
+  test("properly unobserve objects in object", () => {
+    const observer = makeObserver();
+    const state: any = { a: { b: 1 } };
+    observer.observe(state);
+    expect(state.__owl__.rev).toBe(1);
+    const initialA = state.a;
+    expect(initialA.__owl__.rev).toBe(1);
+
+    state.a = "Karlsquell";
+    expect(initialA.__owl__).not.toBeDefined();
+  });
+
+  test("reobserve new object values", () => {
+    const observer = makeObserver();
+    const obj: any = { a: 1 };
+    observer.observe(obj);
+    expect(obj.__owl__.rev).toBe(1);
+    obj.a = { b: 2 };
+    expect(observer.rev).toBe(2);
+    expect(obj.__owl__.rev).toBe(2);
+    expect(obj.a.__owl__.rev).toBe(1);
+
+    obj.a.b = 3;
+    expect(observer.rev).toBe(3);
+    expect(obj.__owl__.rev).toBe(2);
+    expect(obj.a.__owl__.rev).toBe(2);
+  });
+
+  test("deep observe misc changes", () => {
+    const observer = makeObserver();
+    const state: any = { o: { a: 1 }, arr: [1], n: 13 };
+    observer.observe(state);
+    expect(state.__owl__.rev).toBe(1);
+    expect(state.__owl__.deepRev).toBe(1);
+
+    state.o.a = 2;
+    expect(observer.rev).toBe(2);
+    expect(state.__owl__.rev).toBe(1);
+    expect(state.__owl__.deepRev).toBe(2);
+
+    state.arr.push(2);
+    expect(state.__owl__.rev).toBe(1);
+    expect(state.__owl__.deepRev).toBe(3);
+
+    state.n = 155;
+    expect(state.__owl__.rev).toBe(2);
+    expect(state.__owl__.deepRev).toBe(4);
+  });
+
+  test("properly handle already observed state", () => {
+    const observer = makeObserver();
+    const obj1: any = { a: 1 };
+    const obj2: any = { b: 1 };
+    observer.observe(obj1);
+    observer.observe(obj2);
+    expect(obj1.__owl__.rev).toBe(1);
+    expect(obj2.__owl__.rev).toBe(1);
+
+    obj1.a = 2;
+    obj2.b = 3;
+    expect(obj1.__owl__.rev).toBe(2);
+    expect(obj2.__owl__.rev).toBe(2);
+
+    obj2.b = obj1;
+    expect(obj1.__owl__.rev).toBe(2);
+    expect(obj2.__owl__.rev).toBe(3);
+  });
+
+  test("accept cycles in observed state", () => {
+    const observer = makeObserver();
+    const obj1: any = {};
+    const obj2: any = { b: obj1, key: 1 };
+    obj1.a = obj2;
+    observer.observe(obj1);
+    expect(obj1.__owl__.rev).toBe(1);
+    expect(obj2.__owl__.rev).toBe(1);
+
+    obj2.key = 3;
+    expect(obj1.__owl__.rev).toBe(1);
+    expect(obj2.__owl__.rev).toBe(2);
+  });
+});
diff --git a/tests/store.test.ts b/tests/store.test.ts
index 0b07d704..61f29251 100644
--- a/tests/store.test.ts
+++ b/tests/store.test.ts
@@ -1,11 +1,11 @@
-import { Store, makeObserver, connect } from "../src/store";
+import { Component, Env } from "../src/component";
+import { connect, Store } from "../src/store";
 import {
-  nextTick,
-  nextMicroTick,
   makeTestFixture,
-  makeTestWEnv
+  makeTestWEnv,
+  nextMicroTick,
+  nextTick
 } from "./helpers";
-import { Env, Component } from "../src/component";
 
 describe("basic use", () => {
   test("commit a mutation", () => {
@@ -171,260 +171,6 @@ describe("basic use", () => {
   });
 });
 
-describe("observer", () => {
-  test("properly observe objects", () => {
-    const observer = makeObserver();
-    const obj: any = {};
-
-    observer.observe(obj);
-    expect(obj.__owl__.rev).toBe(1);
-    expect(observer.rev).toBe(1);
-
-    const ob2: any = { a: 1 };
-    observer.observe(ob2);
-    expect(ob2.__owl__.rev).toBe(1);
-    ob2.a = 2;
-    expect(observer.rev).toBe(2);
-    expect(ob2.__owl__.rev).toBe(2);
-
-    ob2.b = 3;
-    expect(observer.rev).toBe(2);
-    expect(ob2.__owl__.rev).toBe(2);
-
-    observer.set(ob2, "b", 4);
-    expect(observer.rev).toBe(3);
-    expect(ob2.__owl__.rev).toBe(3);
-  });
-
-  test("properly handle null or undefined", () => {
-    const observer = makeObserver();
-    const obj: any = { a: null, b: undefined };
-
-    observer.observe(obj);
-    expect(obj.__owl__.rev).toBe(1);
-    expect(observer.rev).toBe(1);
-
-    obj.a = 3;
-    expect(obj.__owl__.rev).toBe(2);
-
-    obj.b = 5;
-    expect(obj.__owl__.rev).toBe(3);
-
-    obj.a = null;
-    obj.b = undefined;
-    expect(obj.__owl__.rev).toBe(5);
-  });
-
-  test("can change values in array", () => {
-    const observer = makeObserver();
-    const obj: any = { arr: [1, 2] };
-
-    observer.observe(obj);
-    expect(obj.arr.__owl__.rev).toBe(1);
-    expect(observer.rev).toBe(1);
-
-    obj.arr[0] = "nope";
-    expect(obj.arr.__owl__.rev).toBe(1);
-    expect(observer.rev).toBe(1);
-
-    observer.set(obj.arr, 0, "yep");
-    expect(obj.arr.__owl__.rev).toBe(2);
-    expect(observer.rev).toBe(2);
-  });
-
-  test("various object property changes", () => {
-    const observer = makeObserver();
-    const obj: any = { a: 1 };
-    observer.observe(obj);
-    expect(obj.__owl__.rev).toBe(1);
-    obj.a = 2;
-    expect(observer.rev).toBe(2);
-    expect(obj.__owl__.rev).toBe(2);
-
-    // same value again
-    obj.a = 2;
-    expect(observer.rev).toBe(2);
-    expect(obj.__owl__.rev).toBe(2);
-
-    obj.a = 3;
-    expect(observer.rev).toBe(3);
-    expect(obj.__owl__.rev).toBe(3);
-  });
-
-  test("properly observe arrays", () => {
-    const observer = makeObserver();
-    const arr: any = [];
-    observer.observe(arr);
-    expect(arr.__owl__.rev).toBe(1);
-    expect(observer.rev).toBe(1);
-    expect(arr.length).toBe(0);
-
-    arr.push(1);
-    expect(arr.__owl__.rev).toBe(2);
-    expect(observer.rev).toBe(2);
-    expect(arr.length).toBe(1);
-
-    arr.splice(1, 0, "hey");
-    expect(arr.__owl__.rev).toBe(3);
-    expect(observer.rev).toBe(3);
-    expect(arr.length).toBe(2);
-
-    arr.unshift("lindemans");
-    expect(arr.__owl__.rev).toBe(4);
-
-    arr.reverse();
-    expect(arr.__owl__.rev).toBe(5);
-
-    arr.pop();
-    expect(arr.__owl__.rev).toBe(6);
-
-    arr.shift();
-    expect(arr.__owl__.rev).toBe(7);
-
-    arr.sort();
-    expect(arr.__owl__.rev).toBe(8);
-
-    expect(arr).toEqual([1]);
-  });
-
-  test("object pushed into arrays are observed", () => {
-    const observer = makeObserver();
-    const arr: any = [];
-    observer.observe(arr);
-    expect(observer.rev).toBe(1);
-
-    arr.push({ kriek: 5 });
-    expect(observer.rev).toBe(2);
-    expect(arr.__owl__.rev).toBe(2);
-    expect(arr[0].__owl__.rev).toBe(1);
-
-    arr[0].kriek = 6;
-    expect(observer.rev).toBe(3);
-    expect(arr.__owl__.rev).toBe(2);
-    expect(arr[0].__owl__.rev).toBe(2);
-  });
-
-  test("properly observe arrays in object", () => {
-    const observer = makeObserver();
-    const state: any = { arr: [] };
-    observer.observe(state);
-    expect(state.arr.__owl__.rev).toBe(1);
-    expect(observer.rev).toBe(1);
-    expect(state.arr.length).toBe(0);
-
-    state.arr.push(1);
-    expect(state.arr.__owl__.rev).toBe(2);
-    expect(observer.rev).toBe(2);
-    expect(state.arr.length).toBe(1);
-  });
-
-  test("properly observe objects in array", () => {
-    const observer = makeObserver();
-    const state: any = { arr: [{ something: 1 }] };
-    observer.observe(state);
-    expect(state.arr.__owl__.rev).toBe(1);
-    expect(state.arr[0].__owl__.rev).toBe(1);
-
-    state.arr[0].something = 2;
-    expect(state.arr.__owl__.rev).toBe(1);
-    expect(state.arr[0].__owl__.rev).toBe(2);
-  });
-
-  test("properly observe objects in object", () => {
-    const observer = makeObserver();
-    const state: any = { a: { b: 1 } };
-    observer.observe(state);
-    expect(state.__owl__.rev).toBe(1);
-    expect(state.a.__owl__.rev).toBe(1);
-
-    state.a.b = 2;
-    expect(state.__owl__.rev).toBe(1);
-    expect(state.a.__owl__.rev).toBe(2);
-  });
-
-  test("properly unobserve objects in object", () => {
-    const observer = makeObserver();
-    const state: any = { a: { b: 1 } };
-    observer.observe(state);
-    expect(state.__owl__.rev).toBe(1);
-    const initialA = state.a;
-    expect(initialA.__owl__.rev).toBe(1);
-
-    state.a = "Karlsquell";
-    expect(initialA.__owl__).not.toBeDefined();
-  });
-
-  test("reobserve new object values", () => {
-    const observer = makeObserver();
-    const obj: any = { a: 1 };
-    observer.observe(obj);
-    expect(obj.__owl__.rev).toBe(1);
-    obj.a = { b: 2 };
-    expect(observer.rev).toBe(2);
-    expect(obj.__owl__.rev).toBe(2);
-    expect(obj.a.__owl__.rev).toBe(1);
-
-    obj.a.b = 3;
-    expect(observer.rev).toBe(3);
-    expect(obj.__owl__.rev).toBe(2);
-    expect(obj.a.__owl__.rev).toBe(2);
-  });
-
-  test("deep observe misc changes", () => {
-    const observer = makeObserver();
-    const state: any = { o: { a: 1 }, arr: [1], n: 13 };
-    observer.observe(state);
-    expect(state.__owl__.rev).toBe(1);
-    expect(state.__owl__.deepRev).toBe(1);
-
-    state.o.a = 2;
-    expect(observer.rev).toBe(2);
-    expect(state.__owl__.rev).toBe(1);
-    expect(state.__owl__.deepRev).toBe(2);
-
-    state.arr.push(2);
-    expect(state.__owl__.rev).toBe(1);
-    expect(state.__owl__.deepRev).toBe(3);
-
-    state.n = 155;
-    expect(state.__owl__.rev).toBe(2);
-    expect(state.__owl__.deepRev).toBe(4);
-  });
-
-  test("properly handle already observed state", () => {
-    const observer = makeObserver();
-    const obj1: any = { a: 1 };
-    const obj2: any = { b: 1 };
-    observer.observe(obj1);
-    observer.observe(obj2);
-    expect(obj1.__owl__.rev).toBe(1);
-    expect(obj2.__owl__.rev).toBe(1);
-
-    obj1.a = 2;
-    obj2.b = 3;
-    expect(obj1.__owl__.rev).toBe(2);
-    expect(obj2.__owl__.rev).toBe(2);
-
-    obj2.b = obj1;
-    expect(obj1.__owl__.rev).toBe(2);
-    expect(obj2.__owl__.rev).toBe(3);
-  });
-
-  test("accept cycles in observed state", () => {
-    const observer = makeObserver();
-    const obj1: any = {};
-    const obj2: any = { b: obj1, key: 1 };
-    obj1.a = obj2;
-    observer.observe(obj1);
-    expect(obj1.__owl__.rev).toBe(1);
-    expect(obj2.__owl__.rev).toBe(1);
-
-    obj2.key = 3;
-    expect(obj1.__owl__.rev).toBe(1);
-    expect(obj2.__owl__.rev).toBe(2);
-  });
-});
-
 describe("advanced state properties", () => {
   test("state in the store is reference equal after mutation", async () => {
     const state = {};
@@ -845,7 +591,7 @@ describe("connecting a component to store", () => {
       return {
         selected: state.beers[props.id],
         consumed: state.beers[state.consumedID] || null,
-        taster: state.taster,
+        taster: state.taster
       };
     })(Beer);
 
@@ -866,7 +612,7 @@ describe("connecting a component to store", () => {
       },
       renameBeer({ state }, { beerId, name }) {
         state.beers[beerId].name = name;
-      },
+      }
     };
     const state = {
       beers: {
@@ -880,28 +626,42 @@ describe("connecting a component to store", () => {
     const app = new App(env);
 
     await app.mount(fixture);
-    expect(fixture.innerHTML).toBe("<div><div><span>taster:aaron</span></div></div>");
+    expect(fixture.innerHTML).toBe(
+      "<div><div><span>taster:aaron</span></div></div>"
+    );
 
     await app.updateState({ beerId: 1 });
-    expect(fixture.innerHTML).toBe("<div><div><span>taster:aaron</span><span>selected:jupiler</span></div></div>");
+    expect(fixture.innerHTML).toBe(
+      "<div><div><span>taster:aaron</span><span>selected:jupiler</span></div></div>"
+    );
 
     store.commit("renameBeer", { beerId: 1, name: "kwak" });
     await nextTick();
-    expect(fixture.innerHTML).toBe("<div><div><span>taster:aaron</span><span>selected:kwak</span></div></div>");
+    expect(fixture.innerHTML).toBe(
+      "<div><div><span>taster:aaron</span><span>selected:kwak</span></div></div>"
+    );
 
     store.commit("consume", 1);
     await nextTick();
-    expect(fixture.innerHTML).toBe("<div><div><span>taster:aaron</span><span>selected:kwak</span><span>consumed:kwak</span></div></div>");
+    expect(fixture.innerHTML).toBe(
+      "<div><div><span>taster:aaron</span><span>selected:kwak</span><span>consumed:kwak</span></div></div>"
+    );
 
     await app.updateState({ beerId: 0 });
-    expect(fixture.innerHTML).toBe("<div><div><span>taster:aaron</span><span>consumed:kwak</span></div></div>");
+    expect(fixture.innerHTML).toBe(
+      "<div><div><span>taster:aaron</span><span>consumed:kwak</span></div></div>"
+    );
 
     store.commit("renameBeer", { beerId: 1, name: "jupiler" });
     await nextTick();
-    expect(fixture.innerHTML).toBe("<div><div><span>taster:aaron</span><span>consumed:jupiler</span></div></div>");
+    expect(fixture.innerHTML).toBe(
+      "<div><div><span>taster:aaron</span><span>consumed:jupiler</span></div></div>"
+    );
 
     store.commit("changeTaster", "matthieu");
     await nextTick();
-    expect(fixture.innerHTML).toBe("<div><div><span>taster:matthieu</span><span>consumed:jupiler</span></div></div>");
+    expect(fixture.innerHTML).toBe(
+      "<div><div><span>taster:matthieu</span><span>consumed:jupiler</span></div></div>"
+    );
   });
 });