Use different HTTP ports in the wizard tests (#1026)

If we use only one specific port, when we run the tests in parallel only one
job manages to set up the server, and all the others will use the same.
However, the other jobs may need to serve different files, causing unrelated
failures in the tests.

Author: giordano

test/wizard.jl

@@ -54,7 +54,32 @@ function serve_tgz(req)
     HTTP.Response(200, libfoo_tarball_data)
 end
 HTTP.@register(r, "GET", "/*/source.tar.gz", serve_tgz)
-@async HTTP.serve(r, Sockets.localhost, 14444; verbose=false)
+port = -1
+server = Sockets.TCPServer()
+# Try to connect to different ports, in case one is busy.  Important in case we
+# have multiple parallel builds.
+available_ports = 14444:14544
+for i in available_ports
+    try
+        # Update the global server to shut it down when we are done with it.
+        global server = Sockets.listen(Sockets.InetAddr(Sockets.localhost, i))
+    catch e
+        if e isa Base.IOError
+            if i == last(available_ports)
+                # Oh no, this was our last attempt
+                error("No more ports available for the HTTP server")
+            end
+            # If the port is busy, try the next one
+            continue
+        else
+            rethrow(e)
+        end
+    end
+    # All looks good, update the global `port` and start the server
+    global port = i
+    @async HTTP.serve(r, Sockets.localhost, port; server=server, verbose=false)
+    break
+end
 
 function readuntil_sift(io::IO, needle)
     needle = codeunits(needle)
@@ -127,7 +152,7 @@ end
 @testset "Wizard - Downloading" begin
     state = step2_state()
     with_wizard_output(state, Wizard.step2) do ins, outs
-        call_response(ins, outs, "Please enter a URL", "http://127.0.0.1:14444/a/source.tar.gz")
+        call_response(ins, outs, "Please enter a URL", "http://127.0.0.1:$(port)/a/source.tar.gz")
         call_response(ins, outs, "Would you like to download additional sources", "N")
         call_response(ins, outs, "Do you require any (binary) dependencies", "N")
 
@@ -144,7 +169,7 @@ end
         call_response(ins, outs, "Select the preferred LLVM version", "\e[B\e[B\e[B\r")
     end
     # Check that the state is modified appropriately
-    @test state.source_urls == ["http://127.0.0.1:14444/a/source.tar.gz"]
+    @test state.source_urls == ["http://127.0.0.1:$(port)/a/source.tar.gz"]
     @test getfield.(state.source_files, :hash) == [libfoo_tarball_hash]
     @test Set(state.compilers) == Set([:c, :rust, :go])
     @test state.preferred_gcc_version == getversion(available_gcc_builds[1])
@@ -155,9 +180,9 @@ end
     # Test two tar.gz download
     state = step2_state()
     with_wizard_output(state, Wizard.step2) do ins, outs
-        call_response(ins, outs, "Please enter a URL", "http://127.0.0.1:14444/a/source.tar.gz")
+        call_response(ins, outs, "Please enter a URL", "http://127.0.0.1:$(port)/a/source.tar.gz")
         call_response(ins, outs, "Would you like to download additional sources", "Y")
-        call_response(ins, outs, "Please enter a URL", "http://127.0.0.1:14444/b/source.tar.gz")
+        call_response(ins, outs, "Please enter a URL", "http://127.0.0.1:$(port)/b/source.tar.gz")
         call_response(ins, outs, "Would you like to download additional sources", "N")
         call_response(ins, outs, "Do you require any (binary) dependencies", "N")
 
@@ -168,8 +193,8 @@ end
     end
     # Check that the state is modified appropriately
     @test state.source_urls == [
-        "http://127.0.0.1:14444/a/source.tar.gz",
-        "http://127.0.0.1:14444/b/source.tar.gz",
+        "http://127.0.0.1:$(port)/a/source.tar.gz",
+        "http://127.0.0.1:$(port)/b/source.tar.gz",
     ]
     @test getfield.(state.source_files, :hash) == [
         libfoo_tarball_hash,
@@ -193,7 +218,7 @@ end
     # Test failure to resolve a dependency
     state = step2_state()
     @test_logs (:warn, r"Unable to resolve iso_codez_jll") match_mode=:any with_wizard_output(state, Wizard.step2) do ins, outs
-        call_response(ins, outs, "Please enter a URL", "http://127.0.0.1:14444/a/source.tar.gz")
+        call_response(ins, outs, "Please enter a URL", "http://127.0.0.1:$(port)/a/source.tar.gz")
         call_response(ins, outs, "Would you like to download additional sources", "N")
         call_response(ins, outs, "Do you require any (binary) dependencies", "Y")
 
@@ -231,7 +256,7 @@ function step3_state()
     state = Wizard.WizardState()
     state.step = :step34
     state.platforms = [Platform("x86_64", "linux")]
-    state.source_urls = ["http://127.0.0.1:14444/a/source.tar.gz"]
+    state.source_urls = ["http://127.0.0.1:$(port)/a/source.tar.gz"]
     state.source_files = [BinaryBuilder.SetupSource{ArchiveSource}(libfoo_tarball_path, libfoo_tarball_hash, "")]
     state.name = "libfoo"
     state.version = v"1.0.0"
@@ -425,6 +450,7 @@ end
     end
 end
 
+close(server)
 
 @testset "GitHub - authentication" begin
     withenv("GITHUB_TOKEN" => "") do