Demonstrate the error that occurs when pushing a commit with a bad date

Makefile

@@ -90,6 +90,7 @@ go-test-integration:
 
 	# Add our compiled `spokes-receive-pack` to the PATH while running tests:
 	PATH="$(CURDIR)/bin:$(PATH)" \
+	    GIT_CONFIG_SYSTEM="$(CURDIR)/internal/integration/testdata/gitconfig" \
 	    $(GO) test $(TESTINTEGRATIONFLAGS) $(TESTSUITE) 2>&1
 
 	@echo "$(M) disabling failpoints ..."

internal/integration/integration_test.go

@@ -31,13 +31,17 @@ This commit object intentionally broken
 
 type SpokesReceivePackTestSuite struct {
 	suite.Suite
+	suiteDir              string
 	localRepo, remoteRepo string
 }
 
 func (suite *SpokesReceivePackTestSuite) SetupTest() {
 	var err error
 	req := require.New(suite.T())
 
+	pwd, err := os.Getwd()
+	req.NoError(err, "pwd")
+
 	// set up a folder that will be used as a "local" Git repo
 	localRepo, err := os.MkdirTemp("", "local")
 	req.NoError(err, fmt.Sprintf("unable to create the local Git repo: %s", err))
@@ -80,6 +84,7 @@ func (suite *SpokesReceivePackTestSuite) SetupTest() {
 	req.NoError(exec.Command("git", "config", "transfer.hideRefs", "refs/__hidden__").Run())
 
 	// store the state
+	suite.suiteDir = pwd
 	suite.localRepo = localRepo
 	suite.remoteRepo = remoteRepo
 }
@@ -181,6 +186,15 @@ func (suite *SpokesReceivePackTestSuite) TestSpokesReceivePackHiddenRefs() {
 		"should partially fail")
 }
 
+func (suite *SpokesReceivePackTestSuite) TestBadDate() {
+	cmd := exec.Command("git", "-C", filepath.Join(suite.suiteDir, "testdata/bad-date/sha1.git"),
+		"push", "--receive-pack=spokes-receive-pack-wrapper", suite.remoteRepo, "main")
+	out, err := cmd.CombinedOutput()
+	suite.T().Logf("$ git %s\n%s", strings.Join(cmd.Args, " "), out)
+	assert.Error(suite.T(), err, "expect an error a repo with a malformed committer line in a commit")
+	assert.Contains(suite.T(), string(out), " badDate:", "should complain about a bad date")
+}
+
 func (suite *SpokesReceivePackTestSuite) TestWithGovernor() {
 	started := make(chan any)
 	govSock, msgs, cleanup := startFakeGovernor(suite.T(), started, nil)

internal/integration/testdata/gitconfig

@@ -0,0 +1,4 @@
+# This file has a subset of options from our prod /etc/gitconfig.
+
+[receive]
+    fsckObjects = true