[gtksourceview] cmake.lang: add a test file

[Sébastien Wilmet <swilmet src gnome org>]

commit 9479b44ed56e6e8f4b7f0ca7bb8626d321d083cf
Author: Роман Донченко <dpb corrigendum ru>
Date:   Sun Nov 12 22:25:36 2017 +0300

    cmake.lang: add a test file
    
    https://bugzilla.gnome.org/show_bug.cgi?id=790345

 tests/syntax-highlighting/file.cmake |   39 ++++++++++++++++++++++++++++++++++
 1 files changed, 39 insertions(+), 0 deletions(-)
---
diff --git a/tests/syntax-highlighting/file.cmake b/tests/syntax-highlighting/file.cmake
new file mode 100644
index 0000000..0ecbacc
--- /dev/null
+++ b/tests/syntax-highlighting/file.cmake
@@ -0,0 +1,39 @@
+#[=[
+    This is a bracket comment.
+    TODO markers are recognized here.
+]=]
+
+# This is a line comment.
+# TODO markers are recognized here, too.
+
+set(words
+    These are unquoted arguments.
+    They can include variable references: ${var}, $ENV{var},
+    and escape sequences: \n\".)
+
+message("This is an unquoted argument.
+    It can also include variable references: ${APPLE}, $ENV{CC},
+    and escape sequences: \t\ \\.
+    In addition, line continuations: \
+    are allowed.")
+
+message("Variable references can nest: ${x$ENV{y${z}w}v}")
+
+message([==[
+    This is a bracket argument.
+    Variable references (${x}) or escape sequences (\n)
+    are not processed here.
+]==])
+
+# These are examples of legacy unquoted argument syntax
+# from the cmake-language manual page.
+set(arg_examples
+    -Da="b c" -Da=$(v) a" "b"c"d # legacy
+    "-Da=\"b c\"" "-Da=$(v)" "a\" \"b\"c\"d" # quoted equivalents
+)
+unset(arg_examples)
+
+# Control construct example.
+if(a EQUAL 5 AND (s STREQUAL "${x}" OR s MATCHES [[\*]]))
+endif()
+