Fix bug from the last bit of forwarding+beforeRequest fixes

Author: pimterry

src/rules/requests/request-handlers.ts

@@ -470,7 +470,7 @@ export class PassThroughHandler extends PassThroughHandlerDefinition {
                 hostHeader[1] = updateHostHeader;
             } // Otherwise: falsey means don't touch it.
 
-            reqUrl = new URL(`${protocol}//${hostname}${(port ? `:${port}` : '')}/${path}`).toString();
+            reqUrl = new URL(`${protocol}//${hostname}${(port ? `:${port}` : '')}${path}`).toString();
         }
 
         // Override the request details, if a transform or callback is specified:

test/integration/proxying/proxy-transforms.spec.ts

@@ -106,7 +106,11 @@ nodeOnly(() => {
             it("can update the host header when used with beforeRequest", async () => {
                 let remoteEndpointMock = await remoteServer.forGet('/get').thenReply(200, "mocked data");
                 await server.forAnyRequest().thenForwardTo(remoteServer.url, {
-                    beforeRequest: () => {}
+                    beforeRequest: (req) => {
+                        // Forwarding modifications should be applied before beforeRequest:
+                        expect(req.url).to.equal(remoteServer.urlFor('/get'));
+                        expect(req.headers.host).to.equal(`localhost:${remoteServer.port}`);
+                    }
                 });
 
                 await request.get(server.urlFor("/get"));
@@ -118,7 +122,11 @@ nodeOnly(() => {
             it("can avoid updating the host header when used with beforeRequest", async () => {
                 let remoteEndpointMock = await remoteServer.forGet('/get').thenReply(200, "mocked data");
                 await server.forAnyRequest().thenForwardTo(remoteServer.url, {
-                    beforeRequest: () => {},
+                    beforeRequest: (req) => {
+                        // Forwarding modifications should be applied before beforeRequest:
+                        expect(req.url).to.equal(remoteServer.urlFor('/get')); // <-- New destination
+                        expect(req.headers.host).to.equal(`localhost:${server.port}`); // <-- but old Host
+                    },
                     forwarding: { updateHostHeader: false }
                 });
 
@@ -129,7 +137,7 @@ nodeOnly(() => {
             });
 
             it("doesn't override the host header if beforeRequest does instead", async () => {
-                let remoteEndpointMock = await remoteServer.forGet('/get').thenReply(200, "mocked data");
+                await remoteServer.forGet('/get').thenReply(200, "mocked data");
                 await server.forAnyRequest().thenForwardTo(remoteServer.url, {
                     beforeRequest: () => ({ url: 'http://never.test' })
                 });