diff --git a/Makefile b/Makefile
index c7b8f1324..2dc20b3b0 100644
--- a/Makefile
+++ b/Makefile
@@ -191,26 +191,17 @@ find-trailing-spaces:
 	-$(PYTHON) misc/coding_tools/find-trailing-spaces.py -r $(SOURCES)
 	@echo
 
-# The test-desert-island target grabs the tahoe-deps tarball, unpacks it,
-# does a build, then asserts that the build did not try to download anything
-# as it ran. Invoke this on a new tree, or after a 'clean', to make sure the
-# support/lib/ directory is gone.
-
 .PHONY: fetch-and-unpack-deps
 fetch-and-unpack-deps:
-	test -f tahoe-deps.tar.gz || wget https://tahoe-lafs.org/source/tahoe-lafs/deps/tahoe-lafs-deps.tar.gz
-	rm -rf tahoe-deps
-	tar xzf tahoe-lafs-deps.tar.gz
+	@echo "test-and-unpack-deps is obsolete"
 
 .PHONY: test-desert-island
 test-desert-island:
-	$(MAKE) fetch-and-unpack-deps
-	$(MAKE) 2>&1 | tee make.out
-	$(PYTHON) misc/build_helpers/check-build.py make.out no-downloads
+	@echo "test-desert-island is obsolete"
 
 .PHONY: test-pip-install
 test-pip-install:
-	$(PYTHON) misc/build_helpers/test-pip-install.py
+	@echo "test-pip-install is obsolete"
 
 # TARBALL GENERATION
 .PHONY: tarballs
diff --git a/misc/build_helpers/test-pip-install.py b/misc/build_helpers/test-pip-install.py
deleted file mode 100644
index c24e02fa6..000000000
--- a/misc/build_helpers/test-pip-install.py
+++ /dev/null
@@ -1,31 +0,0 @@
-
-import os, shutil
-from subprocess import check_call
-
-# Install tahoe into a new virtualenv, move aside the source tree, run a test
-# with the installed tahoe. This ensures that the installed code isn't
-# depending upon anything from the source tree. Requires 'pip' and
-# 'virtualenv' to be installed, and enough compilers/libraries (libffi-dev)
-# to enable 'pip install'.
-
-# This runs a lot faster if you've cached wheels first. Edit ~/.pip/pip.conf
-# to have [global] wheel-dir=find-links=/HOME/.pip/wheels, then run 'pip
-# wheel .' from the tahoe tree.
-
-assert os.path.exists("Tahoe.home"), "Run this from the top of the source tree."
-VE = "test-pip-install-virtualenv"
-
-print "creating virtualenv.."
-if os.path.exists(VE):
-    shutil.rmtree(VE)
-check_call(["virtualenv", VE])
-print "running 'pip install .' from virtualenv.."
-check_call(["%s/bin/pip" % VE, "install", "."])
-try:
-    print "moving src/ out of the away"
-    os.rename("src", "src-disabled-by-test-pip-install")
-    print "running 'trial allmydata.test.test_web' from virtualenv.."
-    rc = check_call(["%s/bin/trial" % VE, "allmydata.test.test_web"])
-finally:
-    print "moving src/ back"
-    os.rename("src-disabled-by-test-pip-install", "src")