diff --git a/ci/txpull.sh b/ci/txpull.sh
index 4206739dd..610c531d9 100755
--- a/ci/txpull.sh
+++ b/ci/txpull.sh
@@ -2,6 +2,10 @@
 #
 # Fetch the Transifex translations for Calamares and incorporate them
 # into the source tree, adding commits of the different files.
+#
+# Run this (occasionally) at the top-level directory to get
+# new translations. See also CMakeLists.txt and ci/txstats.py
+# for update instructions.
 
 ### INITIAL SETUP
 #
diff --git a/ci/txpush.sh b/ci/txpush.sh
index cf1c3b883..84166fac6 100755
--- a/ci/txpush.sh
+++ b/ci/txpush.sh
@@ -1,7 +1,13 @@
 #!/bin/sh
 #
-# Fetch the Transifex translations for Calamares and incorporate them
-# into the source tree, adding commits of the different files.
+# Extract translations from Calamares source and send them
+# to Transifex.
+#
+# Run this at the top-level.
+#
+# Use the --no-tx option to do the extraction, but not the
+# pushing-to-Transifex part. This can be useful to check for
+# new strings or when testing the tools themselves.
 
 ### INITIAL SETUP
 #
diff --git a/src/modules/testpythonrun.sh b/src/modules/testpythonrun.sh
new file mode 100644
index 000000000..be2b7800b
--- /dev/null
+++ b/src/modules/testpythonrun.sh
@@ -0,0 +1,55 @@
+#! /bin/sh
+
+### Command-line validation
+#
+#
+SRCDIR=$( dirname "$0" )
+test -d "$SRCDIR" || { echo "! Can't find source directory." ; exit 1 ; }
+
+MODULE="$1"
+test -n "$MODULE" || { echo "! Usage: $0 <module>" ; exit 1 ; }
+
+### Run-time validation
+#
+# .. switch SRCDIR to the module that has been found
+BINDIR="$SRCDIR"  # Keep original SRCDIR
+SRCDIR="$SRCDIR/$MODULE"
+XSRCDIR="src/modules/$MODULE"  # In builddir
+TESTDIR="$SRCDIR/tests"
+
+test -x "$BINDIR/testmodule.py" || { echo "! No support script $BINDIR/testmodule.py" ; exit 1 ; }
+test -d "$SRCDIR" || { echo "! Source $SRCDIR is not a directory." ; exit 1 ; }
+test -f "$TESTDIR/1.global" || { echo "! Source $SRCDIR has no tests." ; exit 1 ; }
+
+test -f "libcalamares.so" || { echo "! Run the tests from the build-directory." ; exit 1 ; }
+test -d "$XSRCDIR" || { echo "! No module directory $XSRCDIR in build-dir." ; exit 1 ; }
+
+### Python setup
+#
+#
+export PYTHONPATH=".:$PYTHONPATH"
+PYTHON=$( which python3 2> /dev/null )
+if test -z "$PYTHON" ; then
+	PYTHON=$( which python 2> /dev/null )
+fi
+test -x "$PYTHON" || { echo "! No suitable Python executable found." ; exit 1 ; }
+
+### Test-execution
+#
+#
+C=0
+while true ; do
+	# Might use shell arithmetic, but need other shebang then
+	C=$( expr "$C" + 1 )
+
+	G_CFG="$TESTDIR/$C.global"
+	J_CFG="$TESTDIR/$C.job"
+
+	test -f "$G_CFG" || break
+	if test -f "$J_CFG" ; then
+		$PYTHON "$BINDIR/testmodule.py" "$XSRCDIR" "$G_CFG" "$J_CFG"
+	else
+		$PYTHON "$BINDIR/testmodule.py" "$XSRCDIR" "$G_CFG"
+	fi
+done
+
diff --git a/src/modules/unpackfs/main.py b/src/modules/unpackfs/main.py
index 851335513..436ec6a5c 100644
--- a/src/modules/unpackfs/main.py
+++ b/src/modules/unpackfs/main.py
@@ -30,6 +30,15 @@ import tempfile
 
 from libcalamares import *
 
+import gettext
+_ = gettext.translation("calamares-python",
+                        localedir=utils.gettext_path(),
+                        languages=utils.gettext_languages(),
+                        fallback=True).gettext
+
+def pretty_name():
+    return _("Installing filesystems.")
+
 
 class UnpackEntry:
     """
@@ -61,6 +70,8 @@ def list_excludes(destination):
     """
     lst = []
     extra_mounts = globalstorage.value("extraMounts")
+    if extra_mounts is None:
+        extra_mounts = []
 
     for extra_mount in extra_mounts:
         mount_point = extra_mount["mountPoint"]
@@ -138,7 +149,8 @@ def file_copy(source, dest, progress_cb):
     # https://bugzilla.redhat.com/show_bug.cgi?id=868755#c50
     # for the same issue in Anaconda, which uses a similar workaround.
     if process.returncode != 0 and process.returncode != 23:
-        return "rsync failed with error code {}.".format(process.returncode)
+        utils.warn("rsync failed with error code {}.".format(process.returncode))
+        return _("rsync failed with error code {}.").format(process.returncode)
 
     return None
 
@@ -192,11 +204,10 @@ class UnpackOperation:
 
                 if entry.sourcefs == "squashfs":
                     if shutil.which("unsquashfs") is None:
-                        msg = ("Failed to find unsquashfs, make sure you have "
-                               "the squashfs-tools package installed")
-                        print(msg)
-                        return ("Failed to unpack image",
-                                msg)
+                        utils.warning("Failed to find unsquashfs")
+
+                        return (_("Failed to unpack image \"{}\"").format(entry.source),
+                                _("Failed to find unsquashfs, make sure you have the squashfs-tools package installed"))
 
                     fslist = subprocess.check_output(
                         ["unsquashfs", "-l", entry.source]
@@ -213,7 +224,7 @@ class UnpackOperation:
                 error_msg = self.unpack_image(entry, imgmountdir)
 
                 if error_msg:
-                    return ("Failed to unpack image {}".format(entry.source),
+                    return (_("Failed to unpack image \"{}\"").format(entry.source),
                             error_msg)
 
             return None
@@ -261,55 +272,66 @@ class UnpackOperation:
             subprocess.check_call(["umount", "-l", imgmountdir])
 
 
+def get_supported_filesystems():
+    """
+    Reads /proc/filesystems (the list of supported filesystems
+    for the current kernel) and returns a list of (names of)
+    those filesystems.
+    """
+    PATH_PROCFS = '/proc/filesystems'
+
+    if os.path.isfile(PATH_PROCFS) and os.access(PATH_PROCFS, os.R_OK):
+        with open(PATH_PROCFS, 'r') as procfile:
+            filesystems = procfile.read()
+            filesystems = filesystems.replace(
+                "nodev", "").replace("\t", "").splitlines()
+            return filesystems
+
+    return []
+
+
 def run():
     """
     Unsquash filesystem.
     """
-    PATH_PROCFS = '/proc/filesystems'
-
     root_mount_point = globalstorage.value("rootMountPoint")
 
     if not root_mount_point:
-        return ("No mount point for root partition in globalstorage",
-                "globalstorage does not contain a \"rootMountPoint\" key, "
-                "doing nothing")
+        utils.warning("No mount point for root partition")
+        return (_("No mount point for root partition"),
+                _("globalstorage does not contain a \"rootMountPoint\" key, "
+                "doing nothing"))
 
     if not os.path.exists(root_mount_point):
-        return ("Bad mount point for root partition in globalstorage",
-                "globalstorage[\"rootMountPoint\"] is \"{}\", which does not "
-                "exist, doing nothing".format(root_mount_point))
+        utils.warning("Bad root mount point \"{}\"".format(root_mount_point))
+        return (_("Bad mount point for root partition"),
+                _("rootMountPoint is \"{}\", which does not "
+                "exist, doing nothing").format(root_mount_point))
+
+    supported_filesystems = get_supported_filesystems()
 
     unpack = list()
 
     for entry in job.configuration["unpack"]:
         source = os.path.abspath(entry["source"])
-
         sourcefs = entry["sourcefs"]
 
-        # Get supported filesystems
-        fs_is_supported = False
-
-        if os.path.isfile(PATH_PROCFS) and os.access(PATH_PROCFS, os.R_OK):
-            with open(PATH_PROCFS, 'r') as procfile:
-                filesystems = procfile.read()
-                filesystems = filesystems.replace(
-                    "nodev", "").replace("\t", "").splitlines()
-
-                # Check if the source filesystem is supported
-                for fs in filesystems:
-                    if fs == sourcefs:
-                        fs_is_supported = True
-
-        if not fs_is_supported:
-            return "Bad filesystem", "sourcefs=\"{}\"".format(sourcefs)
+        if sourcefs not in supported_filesystems:
+            utils.warning("The filesystem for \"{}\" ({}) is not supported".format(source, sourcefs))
+            return (_("Bad unsquash configuration"),
+                    _("The filesystem for \"{}\" ({}) is not supported").format(source, sourcefs))
 
         destination = os.path.abspath(root_mount_point + entry["destination"])
 
         if not os.path.exists(source):
-            return "Bad source", "source=\"{}\"".format(source)
+            utils.warning("The source filesystem \"{}\" does not exist".format(source))
+            return (_("Bad unsquash configuration"),
+                    _("The source filesystem \"{}\" does not exist").format(source))
 
         if not os.path.isdir(destination):
-            return "Bad destination", "destination=\"{}\"".format(destination)
+            utils.warning(("The destination \"{}\" in the target system is not a directory").format(destination))
+            return (_("Bad unsquash configuration"),
+                    _("The destination \"{}\" in the target system is not a directory").format(destination))
 
         unpack.append(UnpackEntry(source, sourcefs, destination))
 
diff --git a/src/modules/unpackfs/runtests.sh b/src/modules/unpackfs/runtests.sh
new file mode 100644
index 000000000..2b9b704c0
--- /dev/null
+++ b/src/modules/unpackfs/runtests.sh
@@ -0,0 +1,17 @@
+#! /bin/sh
+SRCDIR=$( dirname "$0" )
+
+# For test 3
+mkdir /tmp/unpackfs-test-run-rootdir3
+
+# For test 7
+mkdir /tmp/unpackfs-test-run-rootdir3/realdest
+
+# Run tests
+sh "$SRCDIR/../testpythonrun.sh" unpackfs
+
+# Cleanup test 7
+rm -rf /tmp/unpackfs-test-run-rootdir3/realdest
+
+# Cleanup test 3
+rmdir /tmp/unpackfs-test-run-rootdir3
diff --git a/src/modules/unpackfs/tests/1.global b/src/modules/unpackfs/tests/1.global
new file mode 100644
index 000000000..02ae840cb
--- /dev/null
+++ b/src/modules/unpackfs/tests/1.global
@@ -0,0 +1,2 @@
+---
+bogus: true
diff --git a/src/modules/unpackfs/tests/2.global b/src/modules/unpackfs/tests/2.global
new file mode 100644
index 000000000..f496ade61
--- /dev/null
+++ b/src/modules/unpackfs/tests/2.global
@@ -0,0 +1,2 @@
+---
+rootMountPoint: /tmp/unpackfs-test-run-rootdir/
diff --git a/src/modules/unpackfs/tests/3.global b/src/modules/unpackfs/tests/3.global
new file mode 100644
index 000000000..2e6b37ab5
--- /dev/null
+++ b/src/modules/unpackfs/tests/3.global
@@ -0,0 +1,2 @@
+---
+rootMountPoint: /tmp/unpackfs-test-run-rootdir3/
diff --git a/src/modules/unpackfs/tests/3.job b/src/modules/unpackfs/tests/3.job
new file mode 100644
index 000000000..429f65b3c
--- /dev/null
+++ b/src/modules/unpackfs/tests/3.job
@@ -0,0 +1,2 @@
+---
+unpack: []
diff --git a/src/modules/unpackfs/tests/4.global b/src/modules/unpackfs/tests/4.global
new file mode 100644
index 000000000..2e6b37ab5
--- /dev/null
+++ b/src/modules/unpackfs/tests/4.global
@@ -0,0 +1,2 @@
+---
+rootMountPoint: /tmp/unpackfs-test-run-rootdir3/
diff --git a/src/modules/unpackfs/tests/4.job b/src/modules/unpackfs/tests/4.job
new file mode 100644
index 000000000..ab76dcbeb
--- /dev/null
+++ b/src/modules/unpackfs/tests/4.job
@@ -0,0 +1,4 @@
+---
+unpack:
+   - source: .
+     sourcefs: bogus
diff --git a/src/modules/unpackfs/tests/5.global b/src/modules/unpackfs/tests/5.global
new file mode 100644
index 000000000..2e6b37ab5
--- /dev/null
+++ b/src/modules/unpackfs/tests/5.global
@@ -0,0 +1,2 @@
+---
+rootMountPoint: /tmp/unpackfs-test-run-rootdir3/
diff --git a/src/modules/unpackfs/tests/5.job b/src/modules/unpackfs/tests/5.job
new file mode 100644
index 000000000..2f8d732d0
--- /dev/null
+++ b/src/modules/unpackfs/tests/5.job
@@ -0,0 +1,5 @@
+---
+unpack:
+   - source: ./fakesource
+     sourcefs: ext4
+     destination: fakedest
diff --git a/src/modules/unpackfs/tests/6.global b/src/modules/unpackfs/tests/6.global
new file mode 100644
index 000000000..2e6b37ab5
--- /dev/null
+++ b/src/modules/unpackfs/tests/6.global
@@ -0,0 +1,2 @@
+---
+rootMountPoint: /tmp/unpackfs-test-run-rootdir3/
diff --git a/src/modules/unpackfs/tests/6.job b/src/modules/unpackfs/tests/6.job
new file mode 100644
index 000000000..c1110a106
--- /dev/null
+++ b/src/modules/unpackfs/tests/6.job
@@ -0,0 +1,5 @@
+---
+unpack:
+   - source: .
+     sourcefs: ext4
+     destination: fakedest
diff --git a/src/modules/unpackfs/tests/7.global b/src/modules/unpackfs/tests/7.global
new file mode 100644
index 000000000..2e6b37ab5
--- /dev/null
+++ b/src/modules/unpackfs/tests/7.global
@@ -0,0 +1,2 @@
+---
+rootMountPoint: /tmp/unpackfs-test-run-rootdir3/
diff --git a/src/modules/unpackfs/tests/7.job b/src/modules/unpackfs/tests/7.job
new file mode 100644
index 000000000..a31068e5d
--- /dev/null
+++ b/src/modules/unpackfs/tests/7.job
@@ -0,0 +1,5 @@
+---
+unpack:
+   - source: .
+     sourcefs: ext4
+     destination: realdest