diff --git a/modules/mesh-build-go/cmd/mesh-build-go/testdata/captured/toolchain-go-entry.txt b/modules/mesh-build-go/cmd/mesh-build-go/testdata/captured/toolchain-go-entry.txt
index 3ac840c1..dd8082ec 100644
--- a/modules/mesh-build-go/cmd/mesh-build-go/testdata/captured/toolchain-go-entry.txt
+++ b/modules/mesh-build-go/cmd/mesh-build-go/testdata/captured/toolchain-go-entry.txt
@@ -15,7 +15,7 @@
 		// rather than from the linker: two builds of one commit produce the same bytes.
 		//
 		// **And of one build source at two commits** (novox/hq ADR 0267 rule 6, issue 363): a module
-		// built from its repository's root is compiled with the clone's `.git` in view, and Go stamps the commit,
+		// from its repository's root is compiled with the clone's `.git` in view, and Go stamps the commit,
 		// its time and whether the tree was modified into the binary unless told not to — so a merge that
 		// changed only a README made a new digest of an unchanged program.
 		Compile: []string{
diff --git a/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/broken/broken.go b/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/broken/broken.go
new file mode 100644
index 00000000..02f0ddf3
--- /dev/null
+++ b/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/broken/broken.go
@@ -0,0 +1,3 @@
+package broken
+
+func One() int { return "one" }
diff --git a/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/broken/broken_test.go b/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/broken/broken_test.go
new file mode 100644
index 00000000..34eb0541
--- /dev/null
+++ b/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/broken/broken_test.go
@@ -0,0 +1,5 @@
+package broken
+
+import "testing"
+
+func TestOne(t *testing.T) { One() }
diff --git a/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/broken/go.mod b/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/broken/go.mod
new file mode 100644
index 00000000..e0f4d228
--- /dev/null
+++ b/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/broken/go.mod
@@ -0,0 +1,3 @@
+module fixture/broken
+
+go 1.25.0
diff --git a/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/build/cmd/prog/main.go b/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/build/cmd/prog/main.go
new file mode 100644
index 00000000..4037a92a
--- /dev/null
+++ b/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/build/cmd/prog/main.go
@@ -0,0 +1,9 @@
+// Command prog is what the build step of issue 1487 builds in its integration test.
+package main
+
+import "fmt"
+
+// builtFor is stamped by the linker.
+var builtFor string
+
+func main() { fmt.Println("prog built for", builtFor) }
diff --git a/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/build/go.mod b/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/build/go.mod
new file mode 100644
index 00000000..00ca3e6d
--- /dev/null
+++ b/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/build/go.mod
@@ -0,0 +1,3 @@
+module fixture/build
+
+go 1.25.0
diff --git a/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/build/module.json b/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/build/module.json
new file mode 100644
index 00000000..b5439527
--- /dev/null
+++ b/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/build/module.json
@@ -0,0 +1,17 @@
+{
+  "module": "fixture-build",
+  "version": "1",
+  "build": {
+    "artifacts": [
+      {
+        "name": "tools",
+        "kind": "bundle",
+        "language": "go",
+        "system": "arch",
+        "from": "cmd/prog",
+        "binary": "prog-bin",
+        "loads": ["prog-bin"]
+      }
+    ]
+  }
+}
diff --git a/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/digest/a/a.go b/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/digest/a/a.go
new file mode 100644
index 00000000..0f746116
--- /dev/null
+++ b/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/digest/a/a.go
@@ -0,0 +1,4 @@
+package a
+
+// A is what a's tests check.
+func A() int { return 1 }
diff --git a/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/digest/a/a_test.go b/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/digest/a/a_test.go
new file mode 100644
index 00000000..0aaf337a
--- /dev/null
+++ b/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/digest/a/a_test.go
@@ -0,0 +1,15 @@
+package a
+
+import (
+	"os"
+	"testing"
+
+	"fixture/digest/b"
+)
+
+func TestAReadsBAndItsTestdata(t *testing.T) {
+	raw, err := os.ReadFile("testdata/x.txt")
+	if err != nil || A()+b.B() != 3 || len(raw) == 0 {
+		t.Fatal("a")
+	}
+}
diff --git a/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/digest/a/testdata/x.txt b/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/digest/a/testdata/x.txt
new file mode 100644
index 00000000..587be6b4
--- /dev/null
+++ b/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/digest/a/testdata/x.txt
@@ -0,0 +1 @@
+x
diff --git a/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/digest/b/b.go b/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/digest/b/b.go
new file mode 100644
index 00000000..690fd406
--- /dev/null
+++ b/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/digest/b/b.go
@@ -0,0 +1,4 @@
+package b
+
+// B is reached by a's tests.
+func B() int { return 2 }
diff --git a/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/digest/c/c.go b/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/digest/c/c.go
new file mode 100644
index 00000000..467fd27e
--- /dev/null
+++ b/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/digest/c/c.go
@@ -0,0 +1,6 @@
+package c
+
+import _ "embed"
+
+//go:embed note.txt
+var Note string
diff --git a/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/digest/c/c_test.go b/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/digest/c/c_test.go
new file mode 100644
index 00000000..4ab9f706
--- /dev/null
+++ b/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/digest/c/c_test.go
@@ -0,0 +1,9 @@
+package c
+
+import "testing"
+
+func TestCHasANote(t *testing.T) {
+	if Note == "" {
+		t.Fatal("c")
+	}
+}
diff --git a/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/digest/c/note.txt b/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/digest/c/note.txt
new file mode 100644
index 00000000..519dd581
--- /dev/null
+++ b/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/digest/c/note.txt
@@ -0,0 +1 @@
+note
diff --git a/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/digest/d/d.go b/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/digest/d/d.go
new file mode 100644
index 00000000..9cd66d1a
--- /dev/null
+++ b/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/digest/d/d.go
@@ -0,0 +1,4 @@
+package d
+
+// D is reached by no test.
+func D() int { return 4 }
diff --git a/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/digest/go.mod b/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/digest/go.mod
new file mode 100644
index 00000000..2659cd0a
--- /dev/null
+++ b/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/digest/go.mod
@@ -0,0 +1,3 @@
+module fixture/digest
+
+go 1.25.0
diff --git a/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/empty/empty.go b/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/empty/empty.go
new file mode 100644
index 00000000..d0f06191
--- /dev/null
+++ b/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/empty/empty.go
@@ -0,0 +1,3 @@
+package empty
+
+func Nothing() {}
diff --git a/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/empty/go.mod b/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/empty/go.mod
new file mode 100644
index 00000000..ac1acaba
--- /dev/null
+++ b/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/empty/go.mod
@@ -0,0 +1,3 @@
+module fixture/empty
+
+go 1.25.0
diff --git a/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/failing/bad/bad.go b/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/failing/bad/bad.go
new file mode 100644
index 00000000..526a6282
--- /dev/null
+++ b/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/failing/bad/bad.go
@@ -0,0 +1,3 @@
+package bad
+
+func Three() int { return 3 }
diff --git a/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/failing/bad/bad_test.go b/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/failing/bad/bad_test.go
new file mode 100644
index 00000000..b0d25fa0
--- /dev/null
+++ b/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/failing/bad/bad_test.go
@@ -0,0 +1,9 @@
+package bad
+
+import "testing"
+
+func TestThreeIsFour(t *testing.T) {
+	if Three() != 4 {
+		t.Fatalf("Three() = %d, want 4", Three())
+	}
+}
diff --git a/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/failing/go.mod b/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/failing/go.mod
new file mode 100644
index 00000000..10b202f0
--- /dev/null
+++ b/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/failing/go.mod
@@ -0,0 +1,3 @@
+module fixture/failing
+
+go 1.25.0
diff --git a/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/failing/good/good.go b/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/failing/good/good.go
new file mode 100644
index 00000000..6022f6a1
--- /dev/null
+++ b/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/failing/good/good.go
@@ -0,0 +1,3 @@
+package good
+
+func Two() int { return 2 }
diff --git a/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/failing/good/good_test.go b/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/failing/good/good_test.go
new file mode 100644
index 00000000..c6392073
--- /dev/null
+++ b/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/failing/good/good_test.go
@@ -0,0 +1,9 @@
+package good
+
+import "testing"
+
+func TestTwo(t *testing.T) {
+	if Two() != 2 {
+		t.Fatal("two")
+	}
+}
diff --git a/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/slow/go.mod b/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/slow/go.mod
new file mode 100644
index 00000000..7f95cab9
--- /dev/null
+++ b/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/slow/go.mod
@@ -0,0 +1,3 @@
+module fixture/slow
+
+go 1.25.0
diff --git a/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/slow/slow.go b/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/slow/slow.go
new file mode 100644
index 00000000..10b49fa5
--- /dev/null
+++ b/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/slow/slow.go
@@ -0,0 +1,3 @@
+package slow
+
+func Zero() int { return 0 }
diff --git a/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/slow/slow_test.go b/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/slow/slow_test.go
new file mode 100644
index 00000000..39a56be8
--- /dev/null
+++ b/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/slow/slow_test.go
@@ -0,0 +1,16 @@
+package slow
+
+import (
+	"testing"
+	"time"
+)
+
+func TestTakesAWhile(t *testing.T) {
+	time.Sleep(60 * time.Millisecond)
+}
+
+func TestQuick(t *testing.T) {
+	if Zero() != 0 {
+		t.Fatal("zero")
+	}
+}
diff --git a/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/store/go.mod b/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/store/go.mod
new file mode 100644
index 00000000..71f77819
--- /dev/null
+++ b/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/store/go.mod
@@ -0,0 +1,3 @@
+module fixture/store
+
+go 1.25.0
diff --git a/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/store/store.go b/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/store/store.go
new file mode 100644
index 00000000..cff0dca8
--- /dev/null
+++ b/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/store/store.go
@@ -0,0 +1,4 @@
+package store
+
+// Name is what the integration test below finds a store and a bus for.
+const Name = "store"
diff --git a/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/store/store_integration_test.go b/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/store/store_integration_test.go
new file mode 100644
index 00000000..9c3e6a40
--- /dev/null
+++ b/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/store/store_integration_test.go
@@ -0,0 +1,37 @@
+//go:build integration
+
+package store
+
+import (
+	"bufio"
+	"net"
+	"net/url"
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+	"time"
+)
+
+// The fixture of issue 1486: the store and the bus a run gives its tests are there, reached as a test reaches them.
+func TestTheStoreAndTheBusAreThere(t *testing.T) {
+	u, err := url.Parse(os.Getenv("MESH_TEST_POSTGRES"))
+	if err != nil || u.Query().Get("host") == "" {
+		t.Fatalf("MESH_TEST_POSTGRES = %q", os.Getenv("MESH_TEST_POSTGRES"))
+	}
+	pg, err := net.DialTimeout("unix", filepath.Join(u.Query().Get("host"), ".s.PGSQL.5432"), 5*time.Second)
+	if err != nil {
+		t.Fatalf("the store's socket: %v", err)
+	}
+	pg.Close()
+
+	bus, err := net.DialTimeout("tcp", strings.TrimPrefix(os.Getenv("MESH_TEST_NATS"), "nats://"), 5*time.Second)
+	if err != nil {
+		t.Fatalf("the bus: %v", err)
+	}
+	defer bus.Close()
+	line, err := bufio.NewReader(bus).ReadString('\n')
+	if err != nil || !strings.HasPrefix(line, "INFO ") || !strings.Contains(line, `"jetstream":true`) {
+		t.Fatalf("the bus said %q (%v), want an INFO line with JetStream on", line, err)
+	}
+}
diff --git a/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/tagged/go.mod b/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/tagged/go.mod
new file mode 100644
index 00000000..4be2fcd2
--- /dev/null
+++ b/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/tagged/go.mod
@@ -0,0 +1,3 @@
+module fixture/tagged
+
+go 1.25.0
diff --git a/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/tagged/tagged.go b/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/tagged/tagged.go
new file mode 100644
index 00000000..9be2b802
--- /dev/null
+++ b/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/tagged/tagged.go
@@ -0,0 +1,3 @@
+package tagged
+
+func One() int { return 1 }
diff --git a/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/tagged/tagged_integration_test.go b/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/tagged/tagged_integration_test.go
new file mode 100644
index 00000000..917c1765
--- /dev/null
+++ b/modules/mesh-build-go/cmd/mesh-build-go/testdata/repos/tagged/tagged_integration_test.go
@@ -0,0 +1,11 @@
+//go:build integration
+
+package tagged
+
+import "testing"
+
+func TestNeedsAStore(t *testing.T) {
+	if One() != 1 {
+		t.Fatal("one")
+	}
+}