diff --git a/src/createDomInterface.test.ts b/src/createDomInterface.test.ts
index 5b2d6d9..a0a61e5 100644
--- a/src/createDomInterface.test.ts
+++ b/src/createDomInterface.test.ts
@@ -1,12 +1,106 @@
-import { describe, it } from "vitest";
+import { describe, it, expect, beforeEach } from "vitest";
 import createDomInterface from "./createDomInterface";
-import JSDOM from "jsdom";
+import { JSDOM } from "jsdom";
 
 describe("Diff Stylesheet processor: RAW inserts", () => {
-  const {
-    ss,
-    processDiffs,
-  } = //createDomInterface();
-    it("Should insert css rules even if ss is empty", () => {});
-  it("It should insert css rules in correct idx", () => {});
+  let ss: any = null;
+  let processDiffs: any;
+  beforeEach(() => {
+    const { document: doc } = new JSDOM().window;
+    const { ss: styles, processDiffs: diffs } = createDomInterface({
+      id: "id",
+      doc,
+    });
+    ss = styles;
+    processDiffs = diffs;
+  });
+  it("Should insert css rules even if ss is empty", () => {
+    const { document: doc } = new JSDOM().window;
+    const { ss, processDiffs } = createDomInterface({ id: "id", doc });
+    processDiffs([{ type: "raw", path: [0], value: "div{background: red}" }]);
+    //@ts-expect-error
+    expect(ss.cssRules[0].selectorText).toBe("div");
+    //@ts-expect-error
+    expect(ss.cssRules[0].style.background).toBe("red");
+  });
+  it("It should insert css rules in correct idx", () => {
+    const { document: doc } = new JSDOM().window;
+    const { ss, processDiffs } = createDomInterface({
+      id: "id",
+      initialCSS: "div {background: red;} @media (max-width: 300px) {}",
+      doc,
+    });
+    processDiffs([
+      { type: "raw", path: [1], value: "body {background: red;}" },
+    ]);
+    console.log(ss.cssRules);
+    //@ts-expect-error
+    expect(ss.cssRules[1].selectorText).toBe("body");
+    //@ts-expect-error
+    expect(ss.cssRules[1].style.background).toBe("red");
+  });
+});
+
+describe("Diff Stylesheet processor: node diff", () => {
+  it("Should delete the node if value is null", () => {
+    const { document: doc } = new JSDOM().window;
+    const { ss, processDiffs } = createDomInterface({
+      id: "id",
+      initialCSS: "div {background: red;} @media (max-width: 300px) {}",
+      doc,
+    });
+
+    expect(ss.cssRules.length).toBe(2);
+    processDiffs([{ type: "node", path: [0], value: null }]);
+    expect(ss.cssRules.length).toBe(1);
+    //@ts-expect-error
+    expect(ss.cssRules[0].selectorText).toBeUndefined();
+  });
+
+  it("Should replace node at position if it exists", () => {
+    const { document: doc } = new JSDOM().window;
+    const { ss, processDiffs } = createDomInterface({
+      id: "id",
+      initialCSS: "div {background: red;} @media (max-width: 300px) {}",
+      doc,
+    });
+
+    processDiffs([
+      { type: "node", path: [0], value: "body {background: red;}" },
+    ]);
+    expect(ss.cssRules.length).toBe(2);
+    //@ts-expect-error
+    expect(ss.cssRules[0].selectorText).toBe("body");
+  });
+});
+
+describe("Diff Stylesheet processor: properties diff", () => {
+  it("Should update the properties of a node correctly, setting them to the new values or deleting them if property is null", () => {
+    const { document: doc } = new JSDOM().window;
+    const { ss, processDiffs } = createDomInterface({
+      id: "id",
+      initialCSS:
+        "div {background: red; color: red;} @media (max-width: 300px) {}",
+      doc,
+    });
+
+    processDiffs([
+      {
+        type: "properties",
+        path: [0],
+        value: {
+          background: null,
+          color: "blue",
+          margin: "10px",
+        },
+      },
+    ]);
+
+    //@ts-expect-error
+    expect(ss.cssRules[0].style.background).toBe("");
+    //@ts-expect-error
+    expect(ss.cssRules[0].style.color).toBe("blue");
+    //@ts-expect-error
+    expect(ss.cssRules[0].style.margin).toBe("10px");
+  });
 });