ScriptFu: move test plugins and install more in unstable build

Move test plugins from /scripts to /scripts/test.
POTFILES.skip that directory.

Add a readme to scripts dir.

Revise readme in scripts/test

Rename test9.scm which tests the new byte type support in Scheme.
Install it in unstable build, it is an important test,
long and sophisticated.

Install contactsheet.scm as a test plugin in unstable build.
See test/meson.build for comments about its issue.

plug-ins/script-fu/scripts/README

@@ -0,0 +1,30 @@
+The files in this directory are:
+   - production plugins
+   - demo plugins
+   - initialization scripts for ScriptFu
+
+Don't put test plugins in this directory, but in subdirectory test.
+
+Production plugins:
+  - installed in a release.
+  - appear in diverse menus, not just Filters.
+  - should be marked for translation, and not in potfiles.skip
+
+Demo plugins:
+  - installed in a release (with goat exercise plugins)
+  - appear in Filters>Development>Demos
+  - FUTURE: marked for translation, and not in potfiles.skip
+
+Initialization scripts
+  - loaded by the TinyScheme interpreter
+  - have suffix .init or .scm
+  - are not plugins
+FUTURE:
+The initialization scripts should all should have suffix .scm
+(like the rest of the Scheme world.)
+They should be in a separate directory
+so advanced users can load library scripts.
+
+The files script-fu-util.scm and script-fu-util-setpt.scm
+are also initialization scripts but loaded differently from .init files.
+FUTURE: unify loading of initialization scripts.

plug-ins/script-fu/scripts/meson.build

@@ -1,4 +1,5 @@
 subdir('images')
+subdir('test')
 
 # scripts interpreted by extension-script-fu, installed to /scripts
 scripts = [
@@ -48,15 +49,6 @@ scripts = [
   'xach-effect.scm',
 ]
 
-if not stable
-  scripts += [
-    'contactsheet.scm',
-    'clothify-v3.scm',
-    'test-sphere.scm',
-    'test-v3.scm',
-  ]
-endif
-
 install_data(
   scripts,
   install_dir: gimpdatadir / 'scripts',

plug-ins/script-fu/scripts/test/contactsheet.scm

@@ -333,4 +333,7 @@
     SF-COLOR   _"Background color" "black"
 )
 
-(script-fu-menu-register "script-fu-contactsheet" "<Image>/Filters/Combine")
+; Originally installed w release in "<Image>/Filters/Combine"
+; Now installed in unstable as a test plugin because
+; it has an open issue: dirstream fails on Windows.
+(script-fu-menu-register "script-fu-contactsheet" "<Image>/Filters/Development/Demos")

plug-ins/script-fu/scripts/test/meson.build

@@ -0,0 +1,42 @@
+# test plugins
+
+# Some, but not all, plugins in this directory are installed in unstable build.
+# None should be installed in a release.
+# None should be translated: not marked or marked but in potfiles.skip.
+
+# scripts interpreted by extension-script-fu, installed to /scripts
+if not stable
+  scripts = [
+    'contactsheet.scm',
+    'clothify-v3.scm',
+    'test-sphere.scm',
+    'test-v3.scm',
+  ]
+endif
+
+install_data(
+  scripts,
+  install_dir: gimpdatadir / 'scripts',
+)
+
+
+# scripts interpreted by gimp-script-fu-interpreter
+# Each installed in subdirectory of /plug-in
+# Each have a shebang and executable permission.
+# Like other interpreted plugins.
+# Lacking a shebang, a .interp file is needed to associate .scm suffix
+
+if not stable
+  scripts_independent = [
+    { 'name': 'test-bytes' },
+  ]
+endif
+
+foreach plugin : scripts_independent
+  name = plugin.get('name')
+  srcs = plugin.get('srcs', name + '.scm')
+
+  install_data(srcs,
+               install_dir: gimpplugindir / 'plug-ins' / name,
+               install_mode: 'rwxr-xr-x')
+endforeach

plug-ins/script-fu/scripts/test/test-bytes.scm

@@ -584,4 +584,4 @@
   SF-STRING "Test name (optional)" ""
 )
 
-(script-fu-menu-register "script-fu-test9" "<Image>/Test")
+(script-fu-menu-register "script-fu-test9" "<Image>/Filters/Development/Demos")

po-script-fu/POTFILES.skip

@@ -50,9 +50,7 @@ plug-ins/print
 plug-ins/python
 plug-ins/screenshot
 plug-ins/script-fu/script-fu-refresh.c
-plug-ins/script-fu/scripts/contactsheet.scm
-plug-ins/script-fu/scripts/clothify-v3.scm
-plug-ins/script-fu/scripts/test-v3.scm
+plug-ins/script-fu/scripts/test
 plug-ins/selection-to-path
 plug-ins/twain
 plug-ins/ui