diff --git a/test/collections/decodeableMap.test.ts b/test/collections/decodeableMap.test.ts
new file mode 100644
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+++ b/test/collections/decodeableMap.test.ts
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+/*
+ * Copyright (c) 2020, salesforce.com, inc.
+ * All rights reserved.
+ * Licensed under the BSD 3-Clause license.
+ * For full license text, see LICENSE.txt file in the repo root or https://opensource.org/licenses/BSD-3-Clause
+ */
+import { expect } from 'chai';
+import * as sinon from 'sinon';
+import { DecodeableMap } from '../../src/collections/decodeableMap';
+
+describe('DecodeableMap', () => {
+  let dMap: DecodeableMap<string, string>;
+  const ENCODED_KEY = 'encodedKey';
+  const DECODED_KEY = 'decodedKey';
+
+  const sandbox = sinon.createSandbox();
+  let hasDecodedSpy: sinon.SinonSpy;
+  let getDecodedSpy: sinon.SinonSpy;
+  let hasMapSpy: sinon.SinonSpy;
+  let getMapSpy: sinon.SinonSpy;
+  let setMapSpy: sinon.SinonSpy;
+  let deleteMapSpy: sinon.SinonSpy;
+
+  beforeEach(() => {
+    dMap = new DecodeableMap([
+      ['Layout-v1%2E1 Layout', ENCODED_KEY],
+      ['Layout-v9.2 Layout', DECODED_KEY],
+    ]);
+    // eslint-disable-next-line @typescript-eslint/no-explicit-any
+    hasDecodedSpy = sandbox.spy(dMap, 'hasDecoded' as any);
+    // eslint-disable-next-line @typescript-eslint/no-explicit-any
+    getDecodedSpy = sandbox.spy(dMap, 'getDecoded' as any);
+    hasMapSpy = sandbox.spy(Map.prototype, 'has');
+    getMapSpy = sandbox.spy(Map.prototype, 'get');
+    setMapSpy = sandbox.spy(Map.prototype, 'set');
+    deleteMapSpy = sandbox.spy(Map.prototype, 'delete');
+  });
+
+  afterEach(() => {
+    sandbox.restore();
+  });
+
+  describe('has()', () => {
+    it('should match on exact key without decoding', () => {
+      expect(dMap.has('Layout-v1%2E1 Layout')).to.be.true;
+      expect(hasMapSpy.called).to.be.true;
+      expect(hasDecodedSpy.called).to.be.false;
+    });
+
+    it('should match encoded key with decoded value', () => {
+      expect(dMap.has('Layout-v1.1 Layout')).to.be.true;
+      expect(hasMapSpy.called).to.be.true;
+      expect(hasDecodedSpy.called).to.be.true;
+    });
+
+    it('should match decoded key with encoded value', () => {
+      expect(dMap.has('Layout-v9%2E2 Layout')).to.be.true;
+      expect(hasMapSpy.called).to.be.true;
+      expect(hasDecodedSpy.called).to.be.true;
+    });
+
+    it('should not match on no existing key', () => {
+      expect(dMap.has('Layout-MISSING Layout')).to.be.false;
+      expect(hasMapSpy.called).to.be.true;
+      expect(hasDecodedSpy.called).to.be.true;
+    });
+  });
+
+  describe('get()', () => {
+    it('should get value with exact key without decoding', () => {
+      expect(dMap.get('Layout-v1%2E1 Layout')).to.equal(ENCODED_KEY);
+      expect(getMapSpy.calledOnce).to.be.true;
+      expect(getDecodedSpy.called).to.be.false;
+    });
+
+    it('should get value of encoded key using decoded key', () => {
+      expect(dMap.get('Layout-v1.1 Layout')).to.equal(ENCODED_KEY);
+      expect(getMapSpy.calledTwice).to.be.true;
+      expect(getDecodedSpy.calledOnce).to.be.true;
+    });
+
+    it('should get value of decoded key using encoded key', () => {
+      expect(dMap.get('Layout-v9%2E2 Layout')).to.equal(DECODED_KEY);
+      expect(getMapSpy.calledTwice).to.be.true;
+      expect(getDecodedSpy.calledOnce).to.be.true;
+    });
+
+    it('should return undefined on no existing key', () => {
+      expect(dMap.get('Layout-MISSING Layout')).to.be.undefined;
+      expect(getMapSpy.calledOnce).to.be.true;
+      expect(getDecodedSpy.called).to.be.true;
+    });
+  });
+
+  describe('set()', () => {
+    const NEW_VALUE = 'new value from set';
+
+    it('should set value with exact key', () => {
+      expect(dMap.set('Layout-v1%2E1 Layout', NEW_VALUE)).to.equal(dMap);
+      expect(setMapSpy.called).to.be.true;
+      expect(setMapSpy.lastCall.args[0]).to.equal('Layout-v1%2E1 Layout');
+      expect(setMapSpy.lastCall.args[1]).to.equal(NEW_VALUE);
+      expect(dMap.size).to.equal(2);
+      expect(dMap.get('Layout-v1%2E1 Layout')).to.equal(NEW_VALUE);
+    });
+
+    it('should set value of encoded key using decoded key', () => {
+      expect(dMap.set('Layout-v1.1 Layout', NEW_VALUE)).to.equal(dMap);
+      expect(setMapSpy.called).to.be.true;
+      expect(setMapSpy.lastCall.args[0]).to.equal('Layout-v1%2E1 Layout');
+      expect(setMapSpy.lastCall.args[1]).to.equal(NEW_VALUE);
+      expect(dMap.size).to.equal(2);
+      expect(dMap.get('Layout-v1%2E1 Layout')).to.equal(NEW_VALUE);
+    });
+
+    it('should set value of decoded key using encoded key', () => {
+      expect(dMap.set('Layout-v9%2E2 Layout', NEW_VALUE)).to.equal(dMap);
+      expect(setMapSpy.called).to.be.true;
+      expect(setMapSpy.lastCall.args[0]).to.equal('Layout-v9.2 Layout');
+      expect(setMapSpy.lastCall.args[1]).to.equal(NEW_VALUE);
+      expect(dMap.size).to.equal(2);
+      expect(dMap.get('Layout-v9.2 Layout')).to.equal(NEW_VALUE);
+    });
+
+    it('should set new entry on no existing key', () => {
+      expect(dMap.set('Layout-MISSING Layout', NEW_VALUE)).to.equal(dMap);
+      expect(setMapSpy.called).to.be.true;
+      expect(setMapSpy.lastCall.args[0]).to.equal('Layout-MISSING Layout');
+      expect(setMapSpy.lastCall.args[1]).to.equal(NEW_VALUE);
+      expect(dMap.size).to.equal(3);
+      expect(dMap.get('Layout-MISSING Layout')).to.equal(NEW_VALUE);
+    });
+  });
+
+  describe('delete()', () => {
+    it('should delete using exact key', () => {
+      expect(dMap.delete('Layout-v1%2E1 Layout')).to.be.true;
+      expect(deleteMapSpy.calledOnce).to.be.true;
+      expect(deleteMapSpy.firstCall.args[0]).to.equal('Layout-v1%2E1 Layout');
+      expect(dMap.size).to.equal(1);
+      expect(dMap.has('Layout-v1%2E1 Layout')).to.be.false;
+    });
+
+    it('should delete the encoded key using decoded value', () => {
+      expect(dMap.delete('Layout-v1.1 Layout')).to.be.true;
+      expect(deleteMapSpy.calledOnce).to.be.true;
+      expect(deleteMapSpy.firstCall.args[0]).to.equal('Layout-v1%2E1 Layout');
+      expect(dMap.size).to.equal(1);
+      expect(dMap.has('Layout-v1.1 Layout')).to.be.false;
+    });
+
+    it('should delete the decoded key using encoded value', () => {
+      expect(dMap.delete('Layout-v9%2E2 Layout')).to.be.true;
+      expect(deleteMapSpy.calledOnce).to.be.true;
+      expect(deleteMapSpy.firstCall.args[0]).to.equal('Layout-v9.2 Layout');
+      expect(dMap.size).to.equal(1);
+      expect(dMap.has('Layout-v9%2E2 Layout')).to.be.false;
+    });
+
+    it('should not delete on no existing key', () => {
+      expect(dMap.delete('Layout-MISSING Layout')).to.be.false;
+      expect(deleteMapSpy.calledOnce).to.be.true;
+      expect(deleteMapSpy.firstCall.args[0]).to.equal('Layout-MISSING Layout');
+      expect(dMap.size).to.equal(2);
+      expect(dMap.has('Layout-MISSING Layout')).to.be.false;
+    });
+  });
+});