Index: modules/virtchannel_base/memchan.tcl
==================================================================
--- modules/virtchannel_base/memchan.tcl
+++ modules/virtchannel_base/memchan.tcl
@@ -5,11 +5,11 @@
 # Variable string channel (in-memory r/w file, internal variable).
 # Seekable beyond the end of the data, implies appending of 0x00
 # bytes.
 
 # @@ Meta Begin
-# Package tcl::chan::memchan 1.0.2
+# Package tcl::chan::memchan 1.0.4
 # Meta as::author {Andreas Kupries}
 # Meta as::copyright 2009
 # Meta as::license BSD
 # Meta description Re-implementation of Memchan's memchan
 # Meta description channel. Based on Tcl 8.5's channel
@@ -129,22 +129,23 @@
 	# Compute the new location per the arguments.
 
 	set max [string length $content]
 	switch -exact -- $base {
 	    start   { set newloc $offset}
-	    current { set newloc [expr {$at  + $offset    }] }
-	    end     { set newloc [expr {$max + $offset - 1}] }
+	    current { set newloc [expr {$at  + $offset }] }
+	    end     { set newloc [expr {$max + $offset }] }
 	}
 
 	# Check if the new location is beyond the range given by the
 	# content.
 
 	if {$newloc < 0} {
 	    return -code error "Cannot seek before the start of the channel"
-	} elseif {$newloc >= $max} {
+	} elseif {$newloc > $max} {
 	    # We can seek beyond the end of the current contents, add
 	    # a block of zeros.
+	    #puts XXX.PAD.[expr {$newloc - $max}]
 	    append content [binary format @[expr {$newloc - $max}]]
 	}
 
 	# Commit to new location, switch readable events, and report.
 	set at $newloc
@@ -162,7 +163,7 @@
 	my allow read
     }
 }
 
 # # ## ### ##### ######## #############
-package provide tcl::chan::memchan 1.0.3
+package provide tcl::chan::memchan 1.0.4
 return

ADDED   modules/virtchannel_base/memchan.test
Index: modules/virtchannel_base/memchan.test
==================================================================
--- /dev/null
+++ modules/virtchannel_base/memchan.test
@@ -0,0 +1,92 @@
+# -------------------------------------------------------------------------
+# memchan.test -*- tcl -*-
+# (C) 2017 Andreas Kupries. BSD licensed.
+# -------------------------------------------------------------------------
+
+source [file join \
+	[file dirname [file dirname [file join [pwd] [info script]]]] \
+	devtools testutilities.tcl]
+
+testsNeedTcl     8.5
+testsNeedTcltest 2.0
+testsNeed        TclOO 1
+
+support {
+    use virtchannel_core/core.tcl   tcl::chan::core
+    use virtchannel_core/events.tcl tcl::chan::events
+}
+testing {
+    useLocal memchan.tcl tcl::chan::memchan
+}
+
+# -------------------------------------------------------------------------
+
+test tcl-chan-memchan-1.0 {constructor wrong\#args} -body {
+    tcl::chan::memchan X
+} -returnCodes error \
+    -result {wrong # args: should be "tcl::chan::memchan"}
+
+# -------------------------------------------------------------------------
+
+test tcl-chan-memchan-2.0 {tell, initial, empty} -setup {
+    set c [tcl::chan::memchan]
+} -body {
+    tell $c
+} -cleanup {
+    close $c
+    unset c
+} -result 0
+
+test tcl-chan-memchan-2.1 {seek from start, expand, tell} -setup {
+    set c [tcl::chan::memchan]
+} -body {
+    seek $c 10
+    tell $c
+} -cleanup {
+    close $c
+    unset c
+} -result 10
+
+test tcl-chan-memchan-2.2 {seek from end, eof, empty, tell} -setup {
+    set c [tcl::chan::memchan]
+} -body {
+    seek $c 0 end
+    tell $c
+} -cleanup {
+    close $c
+    unset c
+} -result 0
+
+test tcl-chan-memchan-2.3 {seek from end, eof, non-empty, tell} -setup {
+    set c [tcl::chan::memchan]
+    puts $c Hello
+} -body {
+    seek $c 0 end
+    tell $c
+} -cleanup {
+    close $c
+    unset c
+} -result 6
+
+test tcl-chan-memchan-2.4 {seek from end, non-eof, non-empty, tell} -setup {
+    set c [tcl::chan::memchan]
+    puts $c Hello
+} -body {
+    seek $c -6 end
+    tell $c
+} -cleanup {
+    close $c
+    unset c
+} -result 0
+
+# -------------------------------------------------------------------------
+# Explicit cleanup of loaded support classes.
+rename tcl::chan::events {}
+rename tcl::chan::core   {}
+testsuiteCleanup
+return
+
+# Local Variables:
+#  mode: tcl
+#  indent-tabs-mode: nil
+# End:

Index: modules/virtchannel_base/pkgIndex.tcl
==================================================================
--- modules/virtchannel_base/pkgIndex.tcl
+++ modules/virtchannel_base/pkgIndex.tcl
@@ -3,15 +3,15 @@
 package ifneeded tcl::chan::cat 1.0.2      [list source [file join $dir cat.tcl]]
 package ifneeded tcl::chan::facade 1.0.1   [list source [file join $dir facade.tcl]]
 package ifneeded tcl::chan::fifo 1         [list source [file join $dir fifo.tcl]]
 package ifneeded tcl::chan::fifo2 1        [list source [file join $dir fifo2.tcl]]
 package ifneeded tcl::chan::halfpipe 1     [list source [file join $dir halfpipe.tcl]]
-package ifneeded tcl::chan::memchan 1.0.3  [list source [file join $dir memchan.tcl]]
+package ifneeded tcl::chan::memchan 1.0.4  [list source [file join $dir memchan.tcl]]
 package ifneeded tcl::chan::null 1         [list source [file join $dir null.tcl]]
 package ifneeded tcl::chan::nullzero 1     [list source [file join $dir nullzero.tcl]]
 package ifneeded tcl::chan::random 1       [list source [file join $dir random.tcl]]
 package ifneeded tcl::chan::std 1.0.1      [list source [file join $dir std.tcl]]
-package ifneeded tcl::chan::string 1.0.2   [list source [file join $dir string.tcl]]
+package ifneeded tcl::chan::string 1.0.3   [list source [file join $dir string.tcl]]
 package ifneeded tcl::chan::textwindow 1   [list source [file join $dir textwindow.tcl]]
-package ifneeded tcl::chan::variable 1.0.3 [list source [file join $dir variable.tcl]]
+package ifneeded tcl::chan::variable 1.0.4 [list source [file join $dir variable.tcl]]
 package ifneeded tcl::chan::zero 1         [list source [file join $dir zero.tcl]]
 package ifneeded tcl::randomseed 1         [list source [file join $dir randseed.tcl]]

Index: modules/virtchannel_base/string.tcl
==================================================================
--- modules/virtchannel_base/string.tcl
+++ modules/virtchannel_base/string.tcl
@@ -1,11 +1,11 @@
 # -*- tcl -*-
 # # ## ### ##### ######## #############
 # (C) 2009 Andreas Kupries
 
 # @@ Meta Begin
-# Package tcl::chan::string 1
+# Package tcl::chan::string 1.0.3
 # Meta as::author {Andreas Kupries}
 # Meta as::copyright 2009
 # Meta as::license BSD
 # Meta description Implementation of a channel representing
 # Meta description an in-memory read-only random-access
@@ -87,20 +87,20 @@
 	# Compute the new location per the arguments.
 
 	set max [string length $content]
 	switch -exact -- $base {
 	    start   { set newloc $offset}
-	    current { set newloc [expr {$at  + $offset    }] }
-	    end     { set newloc [expr {$max + $offset - 1}] }
+	    current { set newloc [expr {$at  + $offset }] }
+	    end     { set newloc [expr {$max + $offset }] }
 	}
 
 	# Check if the new location is beyond the range given by the
 	# content.
 
 	if {$newloc < 0} {
 	    return -code error "Cannot seek before the start of the channel"
-	} elseif {$newloc >= $max} {
+	} elseif {$newloc > $max} {
 	    return -code error "Cannot seek after the end of the channel"
 	}
 
 	# Commit to new location, switch readable events, and report.
 	set at $newloc
@@ -118,7 +118,7 @@
 	my allow read
     }
 }
 
 # # ## ### ##### ######## #############
-package provide tcl::chan::string 1.0.2
+package provide tcl::chan::string 1.0.3
 return

ADDED   modules/virtchannel_base/string.test
Index: modules/virtchannel_base/string.test
==================================================================
--- /dev/null
+++ modules/virtchannel_base/string.test
@@ -0,0 +1,94 @@
+# -------------------------------------------------------------------------
+# string.test -*- tcl -*-
+# (C) 2017 Andreas Kupries. BSD licensed.
+# -------------------------------------------------------------------------
+
+source [file join \
+	[file dirname [file dirname [file join [pwd] [info script]]]] \
+	devtools testutilities.tcl]
+
+testsNeedTcl     8.5
+testsNeedTcltest 2.0
+testsNeed        TclOO 1
+
+support {
+    use virtchannel_core/core.tcl   tcl::chan::core
+    use virtchannel_core/events.tcl tcl::chan::events
+}
+testing {
+    useLocal string.tcl tcl::chan::string
+}
+
+# -------------------------------------------------------------------------
+
+test tcl-chan-string-1.0 {constructor wrong\#args} -body {
+    tcl::chan::string
+} -returnCodes error \
+    -result {wrong # args: should be "tcl::chan::string content"}
+
+test tcl-chan-string-1.1 {constructor wrong\#args} -body {
+    tcl::chan::string C X
+} -returnCodes error \
+    -result {wrong # args: should be "tcl::chan::string content"}
+
+# -------------------------------------------------------------------------
+
+test tcl-chan-string-2.0 {tell, initial, empty} -setup {
+    set c [tcl::chan::string ""]
+} -body {
+    tell $c
+} -cleanup {
+    close $c
+    unset c
+} -result 0
+
+test tcl-chan-string-2.1 {seek from start beyond eof is error} -setup {
+    set c [tcl::chan::string ""]
+} -body {
+    seek $c 10
+} -cleanup {
+    close $c
+    unset c
+} -returnCodes error -result {Cannot seek after the end of the channel}
+
+test tcl-chan-string-2.2 {seek from end, eof, empty, tell} -setup {
+    set c [tcl::chan::string ""]
+} -body {
+    seek $c 0 end
+    tell $c
+} -cleanup {
+    close $c
+    unset c
+} -result 0
+
+test tcl-chan-string-2.3 {seek from end, eof, non-empty, tell} -setup {
+    set c [tcl::chan::string Hello\n]
+} -body {
+    seek $c 0 end
+    tell $c
+} -cleanup {
+    close $c
+    unset c
+} -result 6
+
+test tcl-chan-string-2.4 {seek from end, non-eof, non-empty, tell} -setup {
+    set c [tcl::chan::string Hello\n]
+} -body {
+    seek $c -6 end
+    tell $c
+} -cleanup {
+    close $c
+    unset c
+} -result 0
+
+# -------------------------------------------------------------------------
+# Explicit cleanup of loaded support classes.
+rename tcl::chan::events {}
+rename tcl::chan::core   {}
+testsuiteCleanup
+return
+
+# Local Variables:
+#  mode: tcl
+#  indent-tabs-mode: nil
+# End:

Index: modules/virtchannel_base/tcllib_memchan.man
==================================================================
--- modules/virtchannel_base/tcllib_memchan.man
+++ modules/virtchannel_base/tcllib_memchan.man
@@ -1,19 +1,20 @@
+[vset VERSION 1.0.4]
 [comment {-*- tcl -*- doctools manpage}]
-[manpage_begin tcl::chan::memchan n 1]
+[manpage_begin tcl::chan::memchan n [vset VERSION]]
 [keywords {in-memory channel}]
 [keywords {reflected channel}]
 [keywords {tip 219}]
 [keywords {virtual channel}]
-[copyright {2009 Andreas Kupries <andreas_kupries@users.sourceforge.net>}]
+[copyright {2009-2017 Andreas Kupries <andreas_kupries@users.sourceforge.net>}]
 [moddesc   {Reflected/virtual channel support}]
 [category  Channels]
 [titledesc {In-memory channel}]
 [require Tcl 8.5]
 [require TclOO]
 [require tcl::chan::events [opt 1]]
-[require tcl::chan::memchan [opt 1]]
+[require tcl::chan::memchan [opt [vset VERSION]]]
 [description]
 [para]
 
 The [package tcl::chan::memchan] package provides a command creating
 channels which live purely in memory. They provide random-access,

Index: modules/virtchannel_base/tcllib_string.man
==================================================================
--- modules/virtchannel_base/tcllib_string.man
+++ modules/virtchannel_base/tcllib_string.man
@@ -1,7 +1,8 @@
+[vset VERSION 1.0.3]
 [comment {-*- tcl -*- doctools manpage}]
-[manpage_begin tcl::chan::string n 1]
+[manpage_begin tcl::chan::string n [vset VERSION]]
 [keywords {in-memory channel}]
 [keywords {reflected channel}]
 [keywords {tip 219}]
 [keywords {virtual channel}]
 [copyright {2009 Andreas Kupries <andreas_kupries@users.sourceforge.net>}]
@@ -9,11 +10,11 @@
 [category  Channels]
 [titledesc {Read-only in-memory channel}]
 [require Tcl 8.5]
 [require TclOO]
 [require tcl::chan::events [opt 1]]
-[require tcl::chan::string [opt 1]]
+[require tcl::chan::string [opt [vset VERSION]]]
 [description]
 [para]
 
 The [package tcl::chan::string] package provides a command creating
 channels which live purely in memory. They provide random-access,

Index: modules/virtchannel_base/tcllib_variable.man
==================================================================
--- modules/virtchannel_base/tcllib_variable.man
+++ modules/virtchannel_base/tcllib_variable.man
@@ -1,7 +1,8 @@
+[vset VERSION 1.0.4]
 [comment {-*- tcl -*- doctools manpage}]
-[manpage_begin tcl::chan::variable n 1]
+[manpage_begin tcl::chan::variable n [vset VERSION]]
 [keywords {in-memory channel}]
 [keywords {reflected channel}]
 [keywords {tip 219}]
 [keywords {virtual channel}]
 [copyright {2009 Andreas Kupries <andreas_kupries@users.sourceforge.net>}]
@@ -9,11 +10,11 @@
 [category  Channels]
 [titledesc {In-memory channel using variable for storage}]
 [require Tcl 8.5]
 [require TclOO]
 [require tcl::chan::events [opt 1]]
-[require tcl::chan::variable [opt 1]]
+[require tcl::chan::variable [opt [vset VERSION]]]
 [description]
 [para]
 
 The [package tcl::chan::variable] package provides a command creating
 channels which live purely in memory. They provide random-access,

Index: modules/virtchannel_base/variable.tcl
==================================================================
--- modules/virtchannel_base/variable.tcl
+++ modules/virtchannel_base/variable.tcl
@@ -1,11 +1,11 @@
 # -*- tcl -*-
 # # ## ### ##### ######## #############
 # (C) 2009 Andreas Kupries
 
 # @@ Meta Begin
-# Package tcl::chan::variable 1.0.2
+# Package tcl::chan::variable 1.0.4
 # Meta as::author {Andreas Kupries}
 # Meta as::copyright 2009
 # Meta as::license BSD
 # Meta description Implementation of a channel representing
 # Meta description an in-memory read-write random-access
@@ -142,20 +142,20 @@
 	# Compute the new location per the arguments.
 
 	set max [string length $content]
 	switch -exact -- $base {
 	    start   { set newloc $offset}
-	    current { set newloc [expr {$at  + $offset    }] }
-	    end     { set newloc [expr {$max + $offset - 1}] }
+	    current { set newloc [expr {$at  + $offset }] }
+	    end     { set newloc [expr {$max + $offset }] }
 	}
 
 	# Check if the new location is beyond the range given by the
 	# content.
 
 	if {$newloc < 0} {
 	    return -code error "Cannot seek before the start of the channel"
-	} elseif {$newloc >= $max} {
+	} elseif {$newloc > $max} {
 	    # We can seek beyond the end of the current contents, add
 	    # a block of zeros.
 	    append content [binary format @[expr {$newloc - $max}]]
 	}
 
@@ -175,7 +175,7 @@
 	my allow read
     }
 }
 
 # # ## ### ##### ######## #############
-package provide tcl::chan::variable 1.0.3
+package provide tcl::chan::variable 1.0.4
 return

ADDED   modules/virtchannel_base/variable.test
Index: modules/virtchannel_base/variable.test
==================================================================
--- /dev/null
+++ modules/virtchannel_base/variable.test
@@ -0,0 +1,102 @@
+# -------------------------------------------------------------------------
+# variable.test -*- tcl -*-
+# (C) 2017 Andreas Kupries. BSD licensed.
+# -------------------------------------------------------------------------
+
+source [file join \
+	[file dirname [file dirname [file join [pwd] [info script]]]] \
+	devtools testutilities.tcl]
+
+testsNeedTcl     8.5
+testsNeedTcltest 2.0
+testsNeed        TclOO 1
+
+support {
+    use virtchannel_core/core.tcl   tcl::chan::core
+    use virtchannel_core/events.tcl tcl::chan::events
+}
+testing {
+    useLocal variable.tcl tcl::chan::variable
+}
+
+# -------------------------------------------------------------------------
+
+test tcl-chan-variable-1.0 {constructor wrong\#args} -body {
+    tcl::chan::variable
+} -returnCodes error \
+    -result {wrong # args: should be "tcl::chan::variable varname"}
+
+test tcl-chan-variable-1.1 {constructor wrong\#args} -body {
+    tcl::chan::variable V X
+} -returnCodes error \
+    -result {wrong # args: should be "tcl::chan::variable varname"}
+
+# -------------------------------------------------------------------------
+
+test tcl-chan-variable-2.0 {tell, initial, empty} -setup {
+    set content ""
+    set c [tcl::chan::variable content]
+} -body {
+    tell $c
+} -cleanup {
+    close $c
+    unset c content
+} -result 0
+
+test tcl-chan-variable-2.1 {seek from start, expand, tell} -setup {
+    set content ""
+    set c [tcl::chan::variable content]
+} -body {
+    seek $c 10
+    tell $c
+} -cleanup {
+    close $c
+    unset c content
+} -result 10
+
+test tcl-chan-variable-2.2 {seek from end, eof, empty, tell} -setup {
+    set content ""
+    set c [tcl::chan::variable content]
+} -body {
+    seek $c 0 end
+    tell $c
+} -cleanup {
+    close $c
+    unset c content
+} -result 0
+
+test tcl-chan-variable-2.3 {seek from end, eof, non-empty, tell} -setup {
+    set content ""
+    set c [tcl::chan::variable content]
+    puts $c Hello
+} -body {
+    seek $c 0 end
+    tell $c
+} -cleanup {
+    close $c
+    unset c content
+} -result 6
+
+test tcl-chan-variable-2.4 {seek from end, non-eof, non-empty, tell} -setup {
+    set content ""
+    set c [tcl::chan::variable content]
+    puts $c Hello
+} -body {
+    seek $c -6 end
+    tell $c
+} -cleanup {
+    close $c
+    unset c content
+} -result 0
+
+# -------------------------------------------------------------------------
+# Explicit cleanup of loaded support classes.
+rename tcl::chan::events {}
+rename tcl::chan::core   {}
+testsuiteCleanup
+return
+
+# Local Variables:
+#  mode: tcl
+#  indent-tabs-mode: nil
+# End: