test: Convert some more test cases to pytest+pexpect

test/t/Makefile.am

@@ -1,3 +1,5 @@
+SUBDIRS = unit
+
 EXTRA_DIST = \
 	conftest.py \
 	test_2to3.py \

test/t/unit/Makefile.am

@@ -0,0 +1,4 @@
+EXTRA_DIST = \
+	test_tilde.py \
+
+all:

test/t/unit/test_tilde.py

@@ -0,0 +1,20 @@
+import pytest
+
+from conftest import assert_bash_exec
+
+
+@pytest.mark.bashcomp(cmd=None, ignore_env=r"^\+COMPREPLY=")
+class TestUnitTilde(object):
+
+    def test_1(self, bash):
+        assert_bash_exec(bash, "_tilde >/dev/null")
+
+    def test_2(self, bash):
+        """Test environment non-pollution, detected at teardown."""
+        assert_bash_exec(
+            bash,
+            'foo() { local aa="~"; _tilde "$aa"; }; foo; unset foo')
+
+    def test_3(self, bash):
+        """Test for https://bugs.debian.org/766163"""
+        assert_bash_exec(bash, '_tilde ~-o')

test/unit/_tilde.exp

@@ -12,15 +12,6 @@ proc teardown {} {
 setup
 
 
-set test "function should run without errors"
-assert_bash_exec {_tilde > /dev/null} $test
-sync_after_int
-
-set test "function should not pollute environment"
-# NOTE: A possible environment pollution is detected by assert_env_modified() in teardown()
-assert_bash_exec {foo() { local aa="~"; _tilde "$aa"; }; foo; unset foo} $test
-sync_after_int
-
 set failed_find_unique_completion 0
 assert_bash_exec {compgen -u} {} /@ users
 if {![find_unique_completion_pair $users part full]} {
@@ -45,9 +36,5 @@ if {$failed_find_unique_completion} {
     sync_after_int
 }
 
-# Debian #766163
-assert_no_complete "_tilde ~-o"
-sync_after_int
-
 
 teardown