fix: throw error when leading slash is not present in path (#1391)

Given #1391 (comment), we
decided to make nock raise an error whenever the user forgets to add a
leading slash into the intercepted path, instead of adding it itself.

lib/interceptor.js

@@ -18,6 +18,14 @@ try {
 module.exports = Interceptor
 
 function Interceptor(scope, uri, method, requestBody, interceptorOptions) {
+  // Check for leading slash. Uri can be either a string or a regexp, but
+  // we only need to check strings.
+  if (typeof uri === 'string' && /^[^/*]/.test(uri)) {
+    throw Error(
+      "Non-wildcard URL path strings must begin with a slash (otherwise they won't match anything)"
+    )
+  }
+
   this.scope = scope
   this.interceptorMatchHeaders = []
 

tests/test_intercept.js

@@ -106,6 +106,11 @@ test("when request's content-type is json: reply callback's requestBody should a
   scope.done()
 })
 
+test("when the path doesn't include a leading slash it raises an error", function(t) {
+  t.plan(1)
+  t.throws(() => nock('http://example.test').get('no-leading-slash'))
+})
+
 test("when request has no content-type header: reply callback's requestBody should not automatically parse to JSON", async t => {
   const requestBodyFixture = {
     id: 1,