diff --git a/packages/firestore/test/unit/index/ordered_code_writer.test.ts b/packages/firestore/test/unit/index/ordered_code_writer.test.ts
index 0da4c4dbf08..c404b9d45fb 100644
--- a/packages/firestore/test/unit/index/ordered_code_writer.test.ts
+++ b/packages/firestore/test/unit/index/ordered_code_writer.test.ts
@@ -148,7 +148,21 @@ const NUMBER_TEST_CASES: Array<ValueTestCase<number>> = [
   )
 ];
 
-describe('Ordered Code Writer', () => {
+const STRING_TEST_CASES: Array<ValueTestCase<string>> = [
+  new ValueTestCase(
+    "",
+    // Note: This values are taken from the Android reference implementation
+    new Uint8Array([0x00, 0x01]),
+    new Uint8Array([0xff, 0xfe])
+  ),
+  new ValueTestCase(
+    "a",
+    new Uint8Array([0x61, 0x00, 0x01]),
+    new Uint8Array([0x9e, 0xff, 0xfe])
+  ),
+];
+
+describe.only('Ordered Code Writer', () => {
   it('computes number of leading zeros', () => {
     for (let i = 0; i < 0xff; ++i) {
       let zeros = 0;
@@ -164,25 +178,41 @@ describe('Ordered Code Writer', () => {
   });
 
   it('converts numbers to bits', () => {
-    for (let i = 0; i < NUMBER_TEST_CASES.length; ++i) {
-      const bytes = getBytes(NUMBER_TEST_CASES[i].val);
+    verifyEncoding(NUMBER_TEST_CASES);
+  });
+
+  it('orders numbers correctly', () => {
+    verifyOrdering(NUMBER_TEST_CASES);
+  });
+
+  it('converts strings to bits', () => {
+    verifyEncoding(STRING_TEST_CASES);
+  });
+
+  it('orders strings correctly', () => {
+    verifyOrdering(STRING_TEST_CASES);
+  });
+
+  function verifyEncoding(testCases: Array<ValueTestCase<unknown>>) {
+    for (let i = 0; i < testCases.length; ++i) {
+      const bytes = getBytes(testCases[i].val);
       expect(bytes.asc).to.deep.equal(
-        NUMBER_TEST_CASES[i].ascEncoding,
-        'Ascending for ' + NUMBER_TEST_CASES[i].val
+        testCases[i].ascEncoding,
+        'Ascending for ' + testCases[i].val
       );
       expect(bytes.desc).to.deep.equal(
-        NUMBER_TEST_CASES[i].descEncoding,
-        'Descending for ' + NUMBER_TEST_CASES[i].val
+        testCases[i].descEncoding,
+        'Descending for ' + testCases[i].val
       );
     }
-  });
+  }
 
-  it('orders numbers correctly', () => {
-    for (let i = 0; i < NUMBER_TEST_CASES.length; ++i) {
-      for (let j = i; j < NUMBER_TEST_CASES.length; ++j) {
-        const left = NUMBER_TEST_CASES[i].val;
+  function verifyOrdering(testCases: Array<ValueTestCase<unknown>>) {
+    for (let i = 0; i < testCases.length; ++i) {
+      for (let j = i; j < testCases.length; ++j) {
+        const left = testCases[i].val;
         const leftBytes = getBytes(left);
-        const right = NUMBER_TEST_CASES[j].val;
+        const right = testCases[j].val;
         const rightBytes = getBytes(right);
         expect(compare(leftBytes.asc, rightBytes.asc)).to.equal(
           i === j ? 0 : -1,
@@ -194,7 +224,7 @@ describe('Ordered Code Writer', () => {
         );
       }
     }
-  });
+  }
 });
 
 function compare(left: Uint8Array, right: Uint8Array): number {
@@ -215,6 +245,9 @@ function getBytes(val: unknown): { asc: Uint8Array; desc: Uint8Array } {
   if (typeof val === 'number') {
     ascWriter.writeNumberAscending(val);
     descWriter.writeNumberDescending(val);
+  } else if (typeof val === 'string') {
+    ascWriter.writeUtf8Ascending(val);
+    descWriter.writeUtf8Descending(val);
   } else {
     throw new Error('Encoding not yet supported for ' + val);
   }