From 653b6f9504a49aae3e279212854c4b32dd11416e Mon Sep 17 00:00:00 2001
From: clawbot <35+clawbot@noreply.example.org>
Date: Sun, 4 Oct 2026 08:19:19 +0000
Subject: [PATCH] Spend less of make test writing the image and waiting (closes
 #56)

The test phase spends most of its time compiling with the race
detector from an empty build cache; then come writing the test image
and the internal/proxy tests.

- Go's build cache is on a tmpfs in the test phase, so its 137 MB are
  no longer written into the test image.
- TestUpgradedConnectionOutlastsTheTimeouts waits until just past
  shortTimeout after the answer to the upgrade was read, by when every
  timeout has started, rather than 7.5 s, so it ends with the other
  timing tests.
- shortTimeout is written as waitLimit / 2, as its comment says it is.

Model: opus-5-5
---
 Dockerfile                         | 5 ++++-
 internal/proxy/passthrough_test.go | 8 +++++---
 internal/proxy/proxy_test.go       | 6 +++---
 3 files changed, 12 insertions(+), 7 deletions(-)

diff --git a/Dockerfile b/Dockerfile
index 30aace9..79d3ef4 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -29,7 +29,10 @@ RUN go mod download
 
 COPY . .
 
-RUN go test -count=1 -timeout 90s -race -cover ./... || \
+# Go's build cache is kept on a tmpfs, out of the image: nothing uses it
+# after this step, and writing it into the image takes seconds.
+RUN --mount=type=tmpfs,target=/root/.cache/go-build \
+    go test -count=1 -timeout 90s -race -cover ./... || \
     { echo "--- Rerunning with -v for details ---"; \
       go test -count=1 -timeout 90s -race -v ./...; exit 1; }
 
diff --git a/internal/proxy/passthrough_test.go b/internal/proxy/passthrough_test.go
index 8f644bb..c278a60 100644
--- a/internal/proxy/passthrough_test.go
+++ b/internal/proxy/passthrough_test.go
@@ -240,15 +240,17 @@ func TestUpgradedConnectionOutlastsTheTimeouts(t *testing.T) {
 		t.Fatalf("read the answer to the upgrade: %v", err)
 	}
 
+	answered := time.Now()
 	_ = res.Body.Close()
 
 	if res.StatusCode != http.StatusSwitchingProtocols {
 		t.Fatalf("status %d, want %d", res.StatusCode, http.StatusSwitchingProtocols)
 	}
 
-	// Every timeout started before the upgrade was answered: wait past
-	// them all, then use the connection.
-	time.Sleep(3 * shortTimeout / 2)
+	// Every timeout started before the upgrade was answered, the response
+	// timeouts last, at the end of the request: wait until just past
+	// shortTimeout after the answer was read, then use the connection.
+	time.Sleep(time.Until(answered.Add(shortTimeout + 100*time.Millisecond)))
 	send(t, conn, "still here\n")
 
 	echoed, err := reader.ReadString('\n')
diff --git a/internal/proxy/proxy_test.go b/internal/proxy/proxy_test.go
index 0e7dea7..24b33f4 100644
--- a/internal/proxy/proxy_test.go
+++ b/internal/proxy/proxy_test.go
@@ -23,9 +23,9 @@ const (
 	// shortTimeout is what a test sets a timeout to, to see it run out.
 	// It starts before the test has set up its case, such as an upgrade
 	// or the app's buffers filling, so it is as long as the hold-up of the
-	// test process that wantTimedOut allows, waitLimit/2: a shorter one
-	// can run out first on a busy host.
-	shortTimeout = 5 * time.Second
+	// test process that wantTimedOut allows: a shorter one can run out
+	// first on a busy host.
+	shortTimeout = waitLimit / 2
 	// shortTimeoutSetting is shortTimeout as a setting's value.
 	shortTimeoutSetting = "5s"
 	// longTimeoutSetting is a timeout that does not run out in a test.
-- 
2.54.0