patch 8.1.0389: :behave command is not tested

Problem:    :behave command is not tested.
Solution:   Add a test. (Dominique Pelle, closes #3429)
diff --git a/src/Make_all.mak b/src/Make_all.mak
index 79b8b94..8f0f4c1 100644
--- a/src/Make_all.mak
+++ b/src/Make_all.mak
@@ -14,6 +14,7 @@
 	test_autoload \
 	test_backspace_opt \
 	test_backup \
+	test_behave \
 	test_blockedit \
 	test_breakindent \
 	test_bufline \
diff --git a/src/testdir/test_alot.vim b/src/testdir/test_alot.vim
index 7d300a4..ea829e0 100644
--- a/src/testdir/test_alot.vim
+++ b/src/testdir/test_alot.vim
@@ -3,6 +3,7 @@
 
 source test_assign.vim
 source test_backup.vim
+source test_behave.vim
 source test_bufline.vim
 source test_cd.vim
 source test_changedtick.vim
diff --git a/src/testdir/test_behave.vim b/src/testdir/test_behave.vim
new file mode 100644
index 0000000..c26bfe7
--- /dev/null
+++ b/src/testdir/test_behave.vim
@@ -0,0 +1,29 @@
+" Test the :behave command
+
+func Test_behave()
+  behave mswin
+  call assert_equal('mouse,key', &selectmode)
+  call assert_equal('popup', &mousemodel)
+  call assert_equal('startsel,stopsel', &keymodel)
+  call assert_equal('exclusive', &selection)
+
+  behave xterm
+  call assert_equal('', &selectmode)
+  call assert_equal('extend', &mousemodel)
+  call assert_equal('', &keymodel)
+  call assert_equal('inclusive', &selection)
+
+  set selection&
+  set mousemodel&
+  set keymodel&
+  set selection&
+endfunc
+
+func Test_behave_completion()
+  call feedkeys(":behave \<C-A>\<C-B>\"\<CR>", 'tx')
+  call assert_equal('"behave mswin xterm', @:)
+endfunc
+
+func Test_behave_error()
+  call assert_fails('behave x', 'E475:')
+endfunc
diff --git a/src/version.c b/src/version.c
index dce4643..a5f2512 100644
--- a/src/version.c
+++ b/src/version.c
@@ -795,6 +795,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    389,
+/**/
     388,
 /**/
     387,