test/py: test the shell if command

Migrate all most tests from command_ut.c into the Python test system.
This allows the tests to be run against any U-Boot binary that supports
the if command (i.e. where hush is enabled) without requiring that
binary to be permanently bloated with the code from command_ut.

Some tests in command_ut.c can only be executed from C code, since they
test internal (more unit-level) features of various U-Boot APIs. The
migrated tests can all operate directly from the U-Boot console.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
Acked-by: Simon Glass <sjg@chromium.org>

test/py/tests/test_hush_if_test.py

@@ -0,0 +1,154 @@
+# Copyright (c) 2015-2016, NVIDIA CORPORATION. All rights reserved.
+#
+# SPDX-License-Identifier: GPL-2.0
+
+# Test operation of the "if" shell command.
+
+import os
+import os.path
+import pytest
+
+# The list of "if test" conditions to test.
+subtests = (
+    # Base if functionality.
+
+    ('true', True),
+    ('false', False),
+
+    # Basic operators.
+
+    ('test aaa = aaa', True),
+    ('test aaa = bbb', False),
+
+    ('test aaa != bbb', True),
+    ('test aaa != aaa', False),
+
+    ('test aaa < bbb', True),
+    ('test bbb < aaa', False),
+
+    ('test bbb > aaa', True),
+    ('test aaa > bbb', False),
+
+    ('test 123 -eq 123', True),
+    ('test 123 -eq 456', False),
+
+    ('test 123 -ne 456', True),
+    ('test 123 -ne 123', False),
+
+    ('test 123 -lt 456', True),
+    ('test 123 -lt 123', False),
+    ('test 456 -lt 123', False),
+
+    ('test 123 -le 456', True),
+    ('test 123 -le 123', True),
+    ('test 456 -le 123', False),
+
+    ('test 456 -gt 123', True),
+    ('test 123 -gt 123', False),
+    ('test 123 -gt 456', False),
+
+    ('test 456 -ge 123', True),
+    ('test 123 -ge 123', True),
+    ('test 123 -ge 456', False),
+
+    ('test -z ""', True),
+    ('test -z "aaa"', False),
+
+    ('test -n "aaa"', True),
+    ('test -n ""', False),
+
+    # Inversion of simple tests.
+
+    ('test ! aaa = aaa', False),
+    ('test ! aaa = bbb', True),
+    ('test ! ! aaa = aaa', True),
+    ('test ! ! aaa = bbb', False),
+
+    # Binary operators.
+
+    ('test aaa != aaa -o bbb != bbb', False),
+    ('test aaa != aaa -o bbb = bbb', True),
+    ('test aaa = aaa -o bbb != bbb', True),
+    ('test aaa = aaa -o bbb = bbb', True),
+
+    ('test aaa != aaa -a bbb != bbb', False),
+    ('test aaa != aaa -a bbb = bbb', False),
+    ('test aaa = aaa -a bbb != bbb', False),
+    ('test aaa = aaa -a bbb = bbb', True),
+
+    # Inversion within binary operators.
+
+    ('test ! aaa != aaa -o ! bbb != bbb', True),
+    ('test ! aaa != aaa -o ! bbb = bbb', True),
+    ('test ! aaa = aaa -o ! bbb != bbb', True),
+    ('test ! aaa = aaa -o ! bbb = bbb', False),
+
+    ('test ! ! aaa != aaa -o ! ! bbb != bbb', False),
+    ('test ! ! aaa != aaa -o ! ! bbb = bbb', True),
+    ('test ! ! aaa = aaa -o ! ! bbb != bbb', True),
+    ('test ! ! aaa = aaa -o ! ! bbb = bbb', True),
+
+    # -z operator.
+
+    ('test -z "$ut_var_nonexistent"', True),
+    ('test -z "$ut_var_exists"', False),
+)
+
+def exec_hush_if(u_boot_console, expr, result):
+    '''Execute a shell "if" command, and validate its result.'''
+
+    cmd = 'if ' + expr + '; then echo true; else echo false; fi'
+    response = u_boot_console.run_command(cmd)
+    assert response.strip() == str(result).lower()
+
+@pytest.mark.buildconfigspec('sys_hush_parser')
+def test_hush_if_test_setup(u_boot_console):
+    '''Set up environment variables used during the "if" tests.'''
+
+    u_boot_console.run_command('setenv ut_var_nonexistent')
+    u_boot_console.run_command('setenv ut_var_exists 1')
+
+@pytest.mark.buildconfigspec('sys_hush_parser')
+@pytest.mark.parametrize('expr,result', subtests)
+def test_hush_if_test(u_boot_console, expr, result):
+    '''Test a single "if test" condition.'''
+
+    exec_hush_if(u_boot_console, expr, result)
+
+@pytest.mark.buildconfigspec('sys_hush_parser')
+def test_hush_if_test_teardown(u_boot_console):
+    '''Clean up environment variables used during the "if" tests.'''
+
+    u_boot_console.run_command('setenv ut_var_exists')
+
+@pytest.mark.buildconfigspec('sys_hush_parser')
+# We might test this on real filesystems via UMS, DFU, 'save', etc.
+# Of those, only UMS currently allows file removal though.
+@pytest.mark.boardspec('sandbox')
+def test_hush_if_test_host_file_exists(u_boot_console):
+    '''Test the "if test -e" shell command.'''
+
+    test_file = u_boot_console.config.result_dir + \
+        '/creating_this_file_breaks_u_boot_tests'
+
+    try:
+        os.unlink(test_file)
+    except:
+        pass
+    assert not os.path.exists(test_file)
+
+    expr = 'test -e hostfs - ' + test_file
+    exec_hush_if(u_boot_console, expr, False)
+
+    try:
+        with file(test_file, 'wb'):
+            pass
+        assert os.path.exists(test_file)
+
+        expr = 'test -e hostfs - ' + test_file
+        exec_hush_if(u_boot_console, expr, True)
+    finally:
+        os.unlink(test_file)
+
+    expr = 'test -e hostfs - ' + test_file
+    exec_hush_if(u_boot_console, expr, False)