publish: fix stupid error in repro-signing and add integration test

stoopid mistake in ea84014f9b reported
by @CiaranG

fdroidserver/publish.py

@@ -280,7 +280,7 @@ def main():
                 signaturefile, signedfile, manifest = signingfiles
 
                 with open(signaturefile, 'rb') as f:
-                    devfp = common.signer_fingerprint_short(common.get_signature(f.read()))
+                    devfp = common.signer_fingerprint_short(common.get_certificate(f.read()))
                 devsigned = '{}_{}_{}.apk'.format(appid, vercode, devfp)
                 devsignedtmp = os.path.join(tmp_dir, devsigned)
                 shutil.copy(apkfile, devsignedtmp)

tests/run-tests

@@ -1104,6 +1104,35 @@ if have_git_2_3; then
 fi
 
 
+#------------------------------------------------------------------------------#
+echo_header 'test extracting and publishing with developer signature'
+
+REPOROOT=`create_test_dir`
+cd $REPOROOT
+fdroid_init_with_prebuilt_keystore
+echo "accepted_formats = ['txt']" >> config.py
+echo 'keydname = "CN=Birdman, OU=Cell, O=Alcatraz, L=Alcatraz, S=California, C=US"' >> config.py
+test -d metadata || mkdir metadata
+cp $WORKSPACE/tests/metadata/com.politedroid.txt metadata/
+test -d repo || mkdir repo
+test -d unsigned || mkdir unsigned
+cp $WORKSPACE/tests/repo/com.politedroid_6.apk unsigned/
+$fdroid signatures unsigned/com.politedroid_6.apk
+test -d metadata/com.politedroid/signatures/6
+test -f metadata/com.politedroid/signatures/6/MANIFEST.MF
+test -f metadata/com.politedroid/signatures/6/RELEASE.RSA
+test -f metadata/com.politedroid/signatures/6/RELEASE.SF
+! test -f repo/com.politedroid_6.apk
+$fdroid publish
+test -f repo/com.politedroid_6.apk
+if which jarsigner; then
+    jarsigner -verify repo/com.politedroid_6.apk
+fi
+if which apksigner; then
+    apksigner verify repo/com.politedroid_6.apk
+fi
+
+
 #------------------------------------------------------------------------------#
 
 # remove this to prevent git conflicts and complaining