diff --git a/src/allmydata/test/data/node.pem.txt b/src/allmydata/test/data/node.pem.txt
deleted file mode 100644
index dd0928cdd..000000000
--- a/src/allmydata/test/data/node.pem.txt
+++ /dev/null
@@ -1,45 +0,0 @@
------BEGIN CERTIFICATE-----
-MIICojCCAYoCAQEwDQYJKoZIhvcNAQELBQAwFzEVMBMGA1UEAwwMbmV3cGJfdGhp
-bmd5MB4XDTIwMDEwMjAxNDAzM1oXDTIxMDEwMTAxNDAzM1owFzEVMBMGA1UEAwwM
-bmV3cGJfdGhpbmd5MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEA1iNV
-z07PYwZwucl87QlL2TFZvDxD4flZ/p3BZE3DCT5Efn9w2NT4sHXL1e+R/qsDFuNG
-bw1y1TRM0DGK6Wr0XRT2mLQULNgB8y/HrhcSdONsYRyWdj+LimyECKjwh0iSkApv
-Yj/7IOuq6dOoh67YXPdf75OHLShm4+8q8fuwhBL+nuuO4NhZDJKupYHcnuCkcF88
-LN77HKrrgbpyVmeghUkwJMLeJCewvYVlambgWRiuGGexFgAm6laS3rWetOcdm9eg
-FoA9PKNN6xvPatbj99MPoLpBbzsI64M0yT/wTSw1pj/Nom3rwfMa2OH8Kk7c8R/r
-U3xj4ZY1DTlGERvejQIDAQABMA0GCSqGSIb3DQEBCwUAA4IBAQAwyQjQ3ZgtJ3JW
-r3/EPdqSUBamTfXIpOh9rXmRjPpbe+MvenqIzl4q+GnkL5mdEb1e1hdKQZgFQ5Q5
-tbcNIz6h5C07KaNtbqhZCx5c/RUEH87VeXuAuOqZHbZWJ18q0tnk+YgWER2TOkgE
-RI2AslcsJBt88UUOjHX6/7J3KjPFaAjW1QV3TTsHxk14aYDYJwPdz+ijchgbOPQ0
-i+ilhzcB+qQnOC1s4xQSFo+zblTO7EgqM9KpupYfOVFh46P1Mak2W8EDvhz0livl
-OROXJ6nR/13lmQdfVX6T45d+ITBwtmW2nGAh3oI3JlArGKHaW+7qnuHR72q9FSES
-cEYA/wmk
------END CERTIFICATE-----
------BEGIN PRIVATE KEY-----
-MIIEvQIBADANBgkqhkiG9w0BAQEFAASCBKcwggSjAgEAAoIBAQDWI1XPTs9jBnC5
-yXztCUvZMVm8PEPh+Vn+ncFkTcMJPkR+f3DY1PiwdcvV75H+qwMW40ZvDXLVNEzQ
-MYrpavRdFPaYtBQs2AHzL8euFxJ042xhHJZ2P4uKbIQIqPCHSJKQCm9iP/sg66rp
-06iHrthc91/vk4ctKGbj7yrx+7CEEv6e647g2FkMkq6lgdye4KRwXzws3vscquuB
-unJWZ6CFSTAkwt4kJ7C9hWVqZuBZGK4YZ7EWACbqVpLetZ605x2b16AWgD08o03r
-G89q1uP30w+gukFvOwjrgzTJP/BNLDWmP82ibevB8xrY4fwqTtzxH+tTfGPhljUN
-OUYRG96NAgMBAAECggEAJ5xztBx0+nFnisZ9yG8uy6d4XPyc5gE1J4dRDdfgmyYc
-j3XNjx6ePi4cHZ/qVryVnrc+AS7wrgW1q9FuS81QFKPbFdZB4SW3/p85BbgY3uxu
-0Ovz3T3V9y4polx12eCP0/tKLVd+gdF2VTik9Sxfs5rC8VNN7wmJNuK4A/k15sgy
-BIu/R8NlMNGQySNhtccp+dzB8uTyKx5zFZhVvnAK/3YX9BC2V4QBW9JxO4S8N0/9
-48e9Sw/fGCfQ/EFPKGCvTvfuRqJ+4t5k10FygXJ+s+y70ifYi+aSsjJBuranbLJp
-g5TwhuKnTWs8Nth3YRLbcJL4VBIOehjAWy8pDMMtlQKBgQD0O8cHb8cOTGW0BijC
-NDofhA2GooQUUR3WL324PXWZq0DXuBDQhJVBKWO3AYonivhhd/qWO8lea9MEmU41
-nKZ7maS4B8AJLJC08P8GL1uCIE/ezEXEi9JwC1zJiyl595Ap4lSAozH0DwjNvmGL
-5mIdYg0BliqFXbloNJkNlb7INwKBgQDgdGEIWXc5Y1ncWNs6iDIV/t2MlL8vLrP0
-hpkl/QiMndOQyD6JBo0+ZqvOQTSS4NTSxBROjPxvFbEJ3eH8Pmn8gHOf46fzP1OJ
-wlYv0gYzkN4FE/tN6JnO2u9pN0euyyZLM1fnEcrMWColMN8JlWjtA7Gbxm8lkfa4
-3vicaJtlWwKBgQCQYL4ZgVR0+Wit8W4qz+EEPHYafvwBXqp6sXxqa7qXawtb+q3F
-9nqdGLCfwMNA+QA37ksugI1byfXmpBH902r/aiZbvAkj4zpwHH9F0r0PwbY1iSA9
-PkLahX0Gj8OnHFgWynsVyGOBWVnk9oSHxVt+7zWtGG5uhKdUGLPZugocJQKBgB61
-7bzduOFiRZ5PjhdxISE/UQL2Kz6Cbl7rt7Kp72yF/7eUnnHTMqoyFBnRdCcQmi4I
-ZBrnUXbFigamlFAWHhxNWwSqeoVeychUjcRXQT/291nMhRsA02KpNA66YJV6+E9b
-xBA6r/vLqGCUUkAWcFfVpIyC1xxV32MmJvAHpBN3AoGAPF3MUFiO0iKNZfst6Tm3
-rzrldLawDo98DRZ7Yb2kWlWZYqUk/Nvryvo2cns75WGSMDYVbbRp+BY7kZmNYa9K
-iQzKDL54ZRu6V+getJdeAO8yXoCmnZKxt5OHvOSrQMfAmFKSwLwxBbZBfXEyuune
-yfusXLtCgajpreoVIa0xWdQ=
------END PRIVATE KEY-----
diff --git a/src/allmydata/test/test_storage_client.py b/src/allmydata/test/test_storage_client.py
index 913d9bf9c..44e481d52 100644
--- a/src/allmydata/test/test_storage_client.py
+++ b/src/allmydata/test/test_storage_client.py
@@ -520,17 +520,15 @@ class StoragePluginWebPresence(AsyncTestCase):
         )
 
 
+_aCertPEM = Tub().myCertificate.dumpPEM()
 def new_tub():
     """
     Make a new ``Tub`` with a hard-coded private key.
     """
-    # Use a pre-generated key so the tests don't spend a lot of time
-    # generating new ones.
-    data = FilePath(__file__).sibling(b"data")
-    privkey = data.child(b"node.pem.txt")
-    return Tub(
-        certData=privkey.getContent(),
-    )
+    # Use a private key / certificate generated by Tub how it wants.  But just
+    # re-use the same one every time so we don't waste a lot of time
+    # generating them over and over in the tests.
+    return Tub(certData=_aCertPEM)
 
 
 def make_broker(tub_maker=None):