diff --git a/eslint.config.js b/eslint.config.js
index 9e95a0a..d422cb0 100644
--- a/eslint.config.js
+++ b/eslint.config.js
@@ -21,6 +21,6 @@ export default [
 		}
 	},
 	{
-		ignores: ['build/', '.svelte-kit/', 'dist/', 'src/lib/googleMaps.js']
+		ignores: ['build/', '.svelte-kit/', 'dist/', 'src/lib/googleMaps.js', 'coverage']
 	}
 ];
diff --git a/src/lib/obaSdk.js b/src/lib/obaSdk.js
index ab13781..05de54a 100644
--- a/src/lib/obaSdk.js
+++ b/src/lib/obaSdk.js
@@ -9,8 +9,16 @@ const oba = new onebusaway({
 });
 
 export function handleOBAResponse(response, entityName) {
+	if (!response) {
+		throw error(500, `Unable to fetch ${entityName}.`);
+	}
+
+	if (typeof response.code === 'undefined') {
+		throw error(500, `Unable to fetch ${entityName}.`);
+	}
+
 	if (response.code !== 200) {
-		return error(500, `Unable to fetch ${entityName}.`);
+		throw error(500, `Unable to fetch ${entityName}.`);
 	}
 
 	return json(response);
diff --git a/src/tests/lib/obaSdk.test.js b/src/tests/lib/obaSdk.test.js
new file mode 100644
index 0000000..9474cde
--- /dev/null
+++ b/src/tests/lib/obaSdk.test.js
@@ -0,0 +1,140 @@
+import { describe, it, expect, vi, beforeEach } from 'vitest';
+import onebusaway from 'onebusaway-sdk';
+import { handleOBAResponse } from '$lib/obaSdk';
+import { error, json } from '@sveltejs/kit';
+
+// Mock the onebusaway-sdk
+vi.mock('onebusaway-sdk');
+
+// Mock @sveltejs/kit error and json functions
+vi.mock('@sveltejs/kit', () => ({
+	error: vi.fn((status, message) => {
+		throw new Error(message);
+	}),
+	json: vi.fn((data) => ({
+		status: 200,
+		body: data
+	}))
+}));
+
+// Mock environment variables
+vi.mock('$env/static/public', () => ({
+	PUBLIC_OBA_SERVER_URL: 'https://test-api.example.com'
+}));
+
+vi.mock('$env/static/private', () => ({
+	PRIVATE_OBA_API_KEY: 'test-api-key'
+}));
+
+describe('OneBusAway Client', () => {
+	beforeEach(() => {
+		vi.clearAllMocks();
+	});
+
+	describe('OBA Client Initialization', () => {
+		it('should initialize with correct configuration', () => {
+			new onebusaway({
+				baseURL: 'https://test-api.example.com',
+				apiKey: 'test-api-key'
+			});
+
+			expect(onebusaway).toHaveBeenCalledWith({
+				baseURL: 'https://test-api.example.com',
+				apiKey: 'test-api-key'
+			});
+		});
+	});
+
+	describe('handleOBAResponse', () => {
+		it('should return JSON response when status code is 200', () => {
+			const mockResponse = {
+				code: 200,
+				data: {
+					stops: []
+				}
+			};
+
+			const result = handleOBAResponse(mockResponse, 'stops');
+			expect(json).toHaveBeenCalledWith(mockResponse);
+			expect(result.status).toBe(200);
+			expect(result.body).toEqual(mockResponse);
+		});
+
+		it('should throw error when status code is not 200', () => {
+			const mockResponse = {
+				code: 404,
+				data: null
+			};
+
+			expect(() => handleOBAResponse(mockResponse, 'stops')).toThrow(/Unable to fetch stops/);
+			expect(error).toHaveBeenCalledWith(500, 'Unable to fetch stops.');
+		});
+
+		it('should handle undefined response gracefully', () => {
+			expect(() => handleOBAResponse(undefined, 'stops')).toThrow(/Unable to fetch stops/);
+			expect(error).toHaveBeenCalledWith(500, 'Unable to fetch stops.');
+		});
+
+		it('should handle null response gracefully', () => {
+			expect(() => handleOBAResponse(null, 'stops')).toThrow(/Unable to fetch stops/);
+			expect(error).toHaveBeenCalledWith(500, 'Unable to fetch stops.');
+		});
+
+		it('should handle response with missing code gracefully', () => {
+			const mockResponse = {
+				data: {
+					stops: []
+				}
+			};
+
+			expect(() => handleOBAResponse(mockResponse, 'stops')).toThrow(/Unable to fetch stops/);
+			expect(error).toHaveBeenCalledWith(500, 'Unable to fetch stops.');
+		});
+	});
+});
+
+describe('OBA Client Integration', () => {
+	let oba;
+
+	beforeEach(() => {
+		vi.clearAllMocks();
+		oba = new onebusaway({
+			baseURL: 'https://test-api.example.com',
+			apiKey: 'test-api-key'
+		});
+	});
+
+	it('should handle successful API responses', async () => {
+		const mockApiResponse = {
+			code: 200,
+			data: {
+				stops: [{ id: 1, name: 'Test Stop' }]
+			}
+		};
+
+		// Mock a successful API call
+		oba.stops = vi.fn().mockResolvedValue(mockApiResponse);
+
+		const response = await oba.stops();
+		const result = handleOBAResponse(response, 'stops');
+
+		expect(json).toHaveBeenCalledWith(mockApiResponse);
+		expect(result.status).toBe(200);
+		expect(result.body).toEqual(mockApiResponse);
+	});
+
+	it('should handle failed API responses', async () => {
+		const mockApiResponse = {
+			code: 500,
+			data: null
+		};
+
+		// Mock a failed API call
+		oba.stops = vi.fn().mockResolvedValue(mockApiResponse);
+
+		const response = await oba.stops();
+
+		expect(() => handleOBAResponse(response, 'stops')).toThrow(/Unable to fetch stops/);
+		expect(error).toHaveBeenCalledWith(500, 'Unable to fetch stops.');
+	});
+});
diff --git a/src/tests/lib/urls.test.js b/src/tests/lib/urls.test.js
new file mode 100644
index 0000000..ae71f6c
--- /dev/null
+++ b/src/tests/lib/urls.test.js
@@ -0,0 +1,74 @@
+import { describe, it, expect } from 'vitest';
+import { buildURL } from '$lib/urls';
+
+describe('buildURL', () => {
+	it('should build a basic URL with query parameters', () => {
+		const result = buildURL('http://example.com', 'api/data', { key: 'value', page: '1' });
+		expect(result).toBe('http://example.com/api/data?key=value&page=1');
+	});
+
+	it('should handle trailing slashes in baseURL', () => {
+		const result = buildURL('http://example.com/', 'api/data', { key: 'value' });
+		expect(result).toBe('http://example.com/api/data?key=value');
+	});
+
+	it('should handle leading slashes in path', () => {
+		const result = buildURL('http://example.com', '/api/data', { key: 'value' });
+		expect(result).toBe('http://example.com/api/data?key=value');
+	});
+
+	it('should handle both trailing and leading slashes', () => {
+		const result = buildURL('http://example.com/', '/api/data', { key: 'value' });
+		expect(result).toBe('http://example.com/api/data?key=value');
+	});
+
+	it('should handle multiple trailing slashes in baseURL', () => {
+		const result = buildURL('http://example.com///', 'api/data', { key: 'value' });
+		expect(result).toBe('http://example.com/api/data?key=value');
+	});
+
+	it('should handle multiple leading slashes in path', () => {
+		const result = buildURL('http://example.com', '///api/data', { key: 'value' });
+		expect(result).toBe('http://example.com/api/data?key=value');
+	});
+
+	it('should handle empty query parameters', () => {
+		const result = buildURL('http://example.com', 'api/data', {});
+		expect(result).toBe('http://example.com/api/data?');
+	});
+
+	it('should encode query parameter values', () => {
+		const result = buildURL('http://example.com', 'api/data', {
+			key: 'value with spaces',
+			special: '!@#$%'
+		});
+		expect(result).toBe(
+			'http://example.com/api/data?key=value+with+spaces&special=%21%40%23%24%25'
+		);
+	});
+
+	it('should convert undefined values to "undefined" string', () => {
+		const result = buildURL('http://example.com', 'api/data', { key: undefined, value: 'test' });
+		expect(result).toBe('http://example.com/api/data?key=undefined&value=test');
+	});
+
+	it('should convert null values to "null" string', () => {
+		const result = buildURL('http://example.com', 'api/data', { key: null, value: 'test' });
+		expect(result).toBe('http://example.com/api/data?key=null&value=test');
+	});
+
+	it('should convert array to comma-separated string', () => {
+		const result = buildURL('http://example.com', 'api/data', { items: ['a', 'b', 'c'] });
+		expect(result).toBe('http://example.com/api/data?items=a%2Cb%2Cc');
+	});
+
+	it('should handle boolean values', () => {
+		const result = buildURL('http://example.com', 'api/data', { isActive: true, isDeleted: false });
+		expect(result).toBe('http://example.com/api/data?isActive=true&isDeleted=false');
+	});
+
+	it('should handle number values', () => {
+		const result = buildURL('http://example.com', 'api/data', { count: 42, price: 19.99 });
+		expect(result).toBe('http://example.com/api/data?count=42&price=19.99');
+	});
+});
diff --git a/src/tests/lib/utils.test.js b/src/tests/lib/utils.test.js
new file mode 100644
index 0000000..a778a90
--- /dev/null
+++ b/src/tests/lib/utils.test.js
@@ -0,0 +1,107 @@
+import { describe, it, expect, vi, afterEach, beforeEach } from 'vitest';
+import { debounce } from '$lib/utils';
+
+describe('debounce', () => {
+	beforeEach(() => {
+		vi.useFakeTimers();
+	});
+
+	afterEach(() => {
+		vi.restoreAllMocks();
+	});
+
+	it('should call the function only once after the wait time', async () => {
+		const mockFn = vi.fn();
+		const debouncedFn = debounce(mockFn, 100);
+
+		debouncedFn();
+		expect(mockFn).not.toBeCalled();
+
+		vi.advanceTimersByTime(50);
+		expect(mockFn).not.toBeCalled();
+
+		vi.advanceTimersByTime(50);
+		expect(mockFn).toBeCalledTimes(1);
+	});
+
+	it('should reset the timer when called again before wait time', () => {
+		const mockFn = vi.fn();
+		const debouncedFn = debounce(mockFn, 100);
+
+		debouncedFn();
+		vi.advanceTimersByTime(50);
+		debouncedFn();
+		vi.advanceTimersByTime(50);
+		expect(mockFn).not.toBeCalled();
+
+		vi.advanceTimersByTime(50);
+		expect(mockFn).toBeCalledTimes(1);
+	});
+
+	it('should pass arguments to the debounced function', () => {
+		const mockFn = vi.fn();
+		const debouncedFn = debounce(mockFn, 100);
+
+		debouncedFn('test', 123);
+		vi.advanceTimersByTime(100);
+
+		expect(mockFn).toBeCalledWith('test', 123);
+	});
+
+	it('should pass the latest arguments when called multiple times', () => {
+		const mockFn = vi.fn();
+		const debouncedFn = debounce(mockFn, 100);
+
+		debouncedFn('first', 1);
+		vi.advanceTimersByTime(50);
+
+		debouncedFn('second', 2);
+		vi.advanceTimersByTime(100);
+
+		expect(mockFn).toBeCalledTimes(1);
+		expect(mockFn).toBeCalledWith('second', 2);
+	});
+
+	it('should maintain correct context (this binding)', () => {
+		const context = {
+			value: 'test',
+			method: vi.fn(function () {
+				return this.value;
+			})
+		};
+
+		const debouncedMethod = debounce(context.method, 100);
+		context.debouncedMethod = debouncedMethod;
+
+		context.debouncedMethod();
+		vi.advanceTimersByTime(100);
+
+		expect(context.method).toBeCalledTimes(1);
+		expect(context.method.mock.results[0].value).toBe('test');
+	});
+
+	it('should handle zero wait time', () => {
+		const mockFn = vi.fn();
+		const debouncedFn = debounce(mockFn, 0);
+
+		debouncedFn();
+		vi.advanceTimersByTime(0);
+
+		expect(mockFn).toBeCalledTimes(1);
+	});
+
+	it('should handle multiple rapid calls', () => {
+		const mockFn = vi.fn();
+		const debouncedFn = debounce(mockFn, 100);
+
+		debouncedFn();
+		debouncedFn();
+		debouncedFn();
+		debouncedFn();
+		debouncedFn();
+
+		vi.advanceTimersByTime(100);
+
+		expect(mockFn).toBeCalledTimes(1);
+	});
+});