diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
new file mode 100644
index 0000000..7f0206a
--- /dev/null
+++ b/.github/workflows/ci.yml
@@ -0,0 +1,35 @@
+name: Run Pytest
+
+on:
+  push:
+    branches:
+      - master
+  pull_request:
+    branches:
+      - master
+
+jobs:
+  run_pytest:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        python-version: [3.6, 3.7, 3.8, 3.9]
+
+    steps:
+    - name: Check out repository
+      uses: actions/checkout@v2
+
+    - name: Set up Python ${{ matrix.python-version }}
+      uses: actions/setup-python@v2
+      with:
+        python-version: ${{ matrix.python-version }}
+
+    - name: Install dependencies
+      run: |
+        python -m pip install --upgrade pip
+        pip install pytest
+        pip install pytest-benchmark
+        pip install .
+
+    - name: Run pytest
+      run: pytest pytest/ -v
diff --git a/.gitignore b/.gitignore
index 4a18d79..f576307 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,3 +2,7 @@
 build/
 *.egg-info/
 dist/
+.venv/
+.vscode
+*.egg
+*.eggs/
diff --git a/kconfiglib.py b/kconfiglib.py
index c67895c..5db9318 100644
--- a/kconfiglib.py
+++ b/kconfiglib.py
@@ -570,6 +570,11 @@ def my_other_fn(kconf, name, arg_1, arg_2, ...):
 #
 # Public classes
 #
+class KconfigException(Exception):
+    def __init__(self, msg, file, line):
+        super().__init__(msg)
+        self.file = file
+        self.line = line
 
 
 class Kconfig(object):
@@ -845,6 +850,7 @@ class Kconfig(object):
         "warn_assign_undef",
         "warn_to_stderr",
         "warnings",
+        "configured_syms",
         "y",
 
         # Parsing-related
@@ -960,7 +966,7 @@ def _init(self, filename, warn, warn_to_stderr, encoding):
         # See __init__()
 
         self._encoding = encoding
-
+        self.configured_syms = set()
         self.srctree = os.getenv("srctree", "")
         # A prefix we can reliably strip from glob() results to get a filename
         # relative to $srctree. relpath() can cause issues for symlinks,
@@ -1236,7 +1242,10 @@ def load_config(self, filename=None, replace=True, verbose=None):
         # This stub only exists to make sure _warn_assign_no_prompt gets
         # reenabled
         try:
-            self._load_config(filename, replace)
+            if filename.endswith(".py"):
+                self._load_config_py(filename)
+            else:
+                self._load_config(filename, replace)
         except UnicodeDecodeError as e:
             _decoding_error(e, filename)
         finally:
@@ -1244,6 +1253,50 @@ def load_config(self, filename=None, replace=True, verbose=None):
 
         return ("Loaded" if replace else "Merged") + msg
 
+    def _load_config_py(self, filename):
+
+        assert filename.endswith(".py")
+        # Get directory from filename, if relative directory then take use .
+        base_dir = os.path.dirname(filename) or "."
+
+        config = """
+import os
+import traceback
+
+def kconfig_import(rel_path):
+    conf_globals=globals()
+    global _rel_dir
+    full_path = os.path.join(_rel_dir, rel_path)
+    _rel_dir = os.path.dirname(os.path.realpath(full_path))
+    with open(full_path, "r") as f:
+        config = f.read()
+    try:
+        exec(config, conf_globals)
+    except KconfigException as exc:
+        raise exc
+    except Exception as exc:
+        tb = exc.__traceback__
+        lineno = traceback.extract_tb(tb)[1].lineno
+        exc.file = full_path
+        exc.line = lineno
+        raise KconfigException(str(exc), full_path, lineno)
+
+"""
+        config += f"kconfig_import(\"{filename}\")"
+
+        conf_globals = self.syms
+        conf_globals["_rel_dir"] = base_dir
+        conf_globals.update(self.named_choices)
+        conf_globals['KconfigException'] = KconfigException
+        conf_globals["kconfig_import"] = self._load_config_py
+
+        try:
+            exec(config, conf_globals)
+        except KconfigException as exc:
+            self._warn(str(exc), exc.file, exc.line)
+            raise exc
+
+
     def _load_config(self, filename, replace):
         with self._open_config(filename) as f:
             if replace:
@@ -4264,6 +4317,7 @@ class Symbol(object):
         "selects",
         "user_value",
         "weak_rev_dep",
+        "_attempted_value"
     )
 
     #
@@ -4283,6 +4337,40 @@ def type(self):
 
         return self.orig_type
 
+    @property
+    def val(self):
+        if self.type == BOOL or self.type == TRISTATE:
+            if self.tri_value == 2:
+                return True
+            elif self.tri_value == 0:
+                return False
+        elif self.type == INT or self.type == HEX:
+            return int(self.str_value)
+        else:
+            return self.str_value
+
+    @val.setter
+    def val(self, value):
+        self.kconfig.configured_syms.add(self)
+        self._attempted_value = value
+        if self.type == BOOL or self.type == TRISTATE:
+            if value:
+                self.set_value(2)
+            else:
+                self.set_value(0)
+        else:
+            self.set_value(str(value))
+        self.check_val()
+
+    def check_val(self):
+        for ref_sym in self.kconfig.configured_syms:
+            if ref_sym._attempted_value:
+                if ref_sym.val != ref_sym._attempted_value:
+                    if ref_sym == self:
+                        raise ValueError("Could not set {} to {} from {}".format(ref_sym.name, ref_sym._attempted_value, ref_sym.val))
+                    else:
+                        raise ValueError("Could not set {} to {} from {} due to {}: {}".format(ref_sym.name, ref_sym._attempted_value, ref_sym.val, self.name, self._attempted_value))
+
     @property
     def str_value(self):
         """
@@ -4785,8 +4873,9 @@ def __init__(self):
 
         # - UNKNOWN == 0
         # - _visited is used during tree iteration and dep. loop detection
-        self.orig_type = self._visited = 0
 
+        self._attempted_value = None
+        self.orig_type = self._visited = 0
         self.nodes = []
 
         self.defaults = []
diff --git a/pytest/test_simple_dep/Kconfig b/pytest/test_simple_dep/Kconfig
new file mode 100644
index 0000000..1204489
--- /dev/null
+++ b/pytest/test_simple_dep/Kconfig
@@ -0,0 +1,9 @@
+config FOO
+    bool "FOO prompt"
+
+config BAR
+    bool "BAR prompt"
+    depends on FOO
+
+config BAZ
+    bool "BAZ prompt"
diff --git a/pytest/test_simple_dep/app.config b/pytest/test_simple_dep/app.config
new file mode 100644
index 0000000..7f9c9f4
--- /dev/null
+++ b/pytest/test_simple_dep/app.config
@@ -0,0 +1,2 @@
+FOO = y
+BAR = y
diff --git a/pytest/test_simple_dep/config.conditional.py b/pytest/test_simple_dep/config.conditional.py
new file mode 100644
index 0000000..f5e17c3
--- /dev/null
+++ b/pytest/test_simple_dep/config.conditional.py
@@ -0,0 +1,4 @@
+if FOO.val:
+    BAR.val = True
+else:
+    FOO.val = True
diff --git a/pytest/test_simple_dep/config.import.py b/pytest/test_simple_dep/config.import.py
new file mode 100644
index 0000000..d332ce3
--- /dev/null
+++ b/pytest/test_simple_dep/config.import.py
@@ -0,0 +1 @@
+kconfig_import("config.py")
diff --git a/pytest/test_simple_dep/config.import100.py b/pytest/test_simple_dep/config.import100.py
new file mode 100644
index 0000000..b258056
--- /dev/null
+++ b/pytest/test_simple_dep/config.import100.py
@@ -0,0 +1 @@
+[kconfig_import("config.py") for _ in range(100)]
diff --git a/pytest/test_simple_dep/config.import_dir.py b/pytest/test_simple_dep/config.import_dir.py
new file mode 100644
index 0000000..2467dc5
--- /dev/null
+++ b/pytest/test_simple_dep/config.import_dir.py
@@ -0,0 +1,2 @@
+kconfig_import("config.py")
+kconfig_import("import/config.py")
diff --git a/pytest/test_simple_dep/config.py b/pytest/test_simple_dep/config.py
new file mode 100644
index 0000000..63869e5
--- /dev/null
+++ b/pytest/test_simple_dep/config.py
@@ -0,0 +1,2 @@
+FOO.val = True
+BAR.val = True
diff --git a/pytest/test_simple_dep/config1.py b/pytest/test_simple_dep/config1.py
new file mode 100644
index 0000000..a931a51
--- /dev/null
+++ b/pytest/test_simple_dep/config1.py
@@ -0,0 +1,2 @@
+for _ in range(1):
+    FOO.val = not FOO.val
diff --git a/pytest/test_simple_dep/config100.py b/pytest/test_simple_dep/config100.py
new file mode 100644
index 0000000..50b307b
--- /dev/null
+++ b/pytest/test_simple_dep/config100.py
@@ -0,0 +1,2 @@
+for _ in range(100):
+    FOO.val = not FOO.val
diff --git a/pytest/test_simple_dep/fail.config.exception.py b/pytest/test_simple_dep/fail.config.exception.py
new file mode 100644
index 0000000..b6f8c5f
--- /dev/null
+++ b/pytest/test_simple_dep/fail.config.exception.py
@@ -0,0 +1 @@
+1/0
diff --git a/pytest/test_simple_dep/fail.config.missing_dep.py b/pytest/test_simple_dep/fail.config.missing_dep.py
new file mode 100644
index 0000000..02f9014
--- /dev/null
+++ b/pytest/test_simple_dep/fail.config.missing_dep.py
@@ -0,0 +1 @@
+BAR.val = True
diff --git a/pytest/test_simple_dep/fail.config.removed_dep.py b/pytest/test_simple_dep/fail.config.removed_dep.py
new file mode 100644
index 0000000..9a34102
--- /dev/null
+++ b/pytest/test_simple_dep/fail.config.removed_dep.py
@@ -0,0 +1,4 @@
+FOO.val = True
+BAR.val = True
+# Expect the following to fail since BAR is True and depends on FOO.
+FOO.val = False
diff --git a/pytest/test_simple_dep/import/config.py b/pytest/test_simple_dep/import/config.py
new file mode 100644
index 0000000..401dc86
--- /dev/null
+++ b/pytest/test_simple_dep/import/config.py
@@ -0,0 +1 @@
+BAR.val = False
diff --git a/pytest/test_simple_dep/test_simple_dep.py b/pytest/test_simple_dep/test_simple_dep.py
new file mode 100644
index 0000000..be6ab06
--- /dev/null
+++ b/pytest/test_simple_dep/test_simple_dep.py
@@ -0,0 +1,34 @@
+import os
+import glob
+import kconfiglib
+import pytest
+
+CUR_DIR = os.path.dirname(os.path.realpath(__file__))
+
+@pytest.mark.parametrize("config_file",
+                         sorted(glob.glob(CUR_DIR + '/config*.py',
+                                          recursive=True)))
+def test_configs_should_not_crash(config_file):
+    """Test config files that should not crash.
+
+    No asserts are used as we are just looking for exceptions.
+    """
+    kconfig_path = CUR_DIR + '/Kconfig'
+
+    kconf = kconfiglib.Kconfig(kconfig_path)
+    kconf.load_config(filename=config_file)
+
+
+@pytest.mark.parametrize("config_file",
+                         sorted(glob.glob(CUR_DIR + '/fail.config*.py',
+                                          recursive=True)))
+def test_configs_should_crash(config_file):
+    """Test config files that should not crash.
+
+    No asserts are used as we are just looking for exceptions.
+    """
+    kconfig_path = CUR_DIR + '/Kconfig'
+
+    kconf = kconfiglib.Kconfig(kconfig_path, warn=False)
+    with pytest.raises(Exception):
+        kconf.load_config(filename=config_file)
diff --git a/pytest/test_simple_dep/test_simple_dep_bench.py b/pytest/test_simple_dep/test_simple_dep_bench.py
new file mode 100644
index 0000000..05dec9a
--- /dev/null
+++ b/pytest/test_simple_dep/test_simple_dep_bench.py
@@ -0,0 +1,54 @@
+import os
+import glob
+import kconfiglib
+import pytest
+
+CUR_DIR = os.path.dirname(os.path.realpath(__file__))
+
+
+def test_bench_config(benchmark):
+    """Evaluate the performance standard config file."""
+    kconfig_path = CUR_DIR + '/Kconfig'
+
+    kconf = kconfiglib.Kconfig(kconfig_path)
+    benchmark(kconf.load_config, filename=CUR_DIR + '/app.config')
+
+
+def test_bench_configpy(benchmark):
+    """Evaluate the performance python config."""
+    kconfig_path = CUR_DIR + '/Kconfig'
+
+    kconf = kconfiglib.Kconfig(kconfig_path)
+    benchmark(kconf.load_config, filename=CUR_DIR + '/config.py')
+
+
+def test_bench_import_configpy(benchmark):
+    """Evaluate the performance of importing."""
+    kconfig_path = CUR_DIR + '/Kconfig'
+
+    kconf = kconfiglib.Kconfig(kconfig_path)
+    benchmark(kconf.load_config, filename=CUR_DIR + '/config.import.py')
+
+
+def test_bench_import100_configpy(benchmark):
+    """Evaluate the performance of importing foo 100 times."""
+    kconfig_path = CUR_DIR + '/Kconfig'
+
+    kconf = kconfiglib.Kconfig(kconfig_path)
+    benchmark(kconf.load_config, filename=CUR_DIR + '/config.import100.py')
+
+
+def test_bench_config1_configpy(benchmark):
+    """Evaluate the performance of setting foo 1 time."""
+    kconfig_path = CUR_DIR + '/Kconfig'
+
+    kconf = kconfiglib.Kconfig(kconfig_path)
+    benchmark(kconf.load_config, filename=CUR_DIR + '/config1.py')
+
+
+def test_bench_config100_configpy(benchmark):
+    """Evaluate the performance of setting foo 100 times."""
+    kconfig_path = CUR_DIR + '/Kconfig'
+
+    kconf = kconfiglib.Kconfig(kconfig_path)
+    benchmark(kconf.load_config, filename=CUR_DIR + '/config100.py')
diff --git a/pytest/test_types/Kconfig b/pytest/test_types/Kconfig
new file mode 100644
index 0000000..e73c031
--- /dev/null
+++ b/pytest/test_types/Kconfig
@@ -0,0 +1,14 @@
+config TEST_BOOL
+    bool "TEST_BOOL prompt"
+
+config TEST_TRISTATE
+    tristate "TEST_TRISTATE prompt"
+
+config TEST_STRING
+    string "TEST_STRING prompt"
+
+config TEST_INT
+    int "TEST_INT prompt"
+
+config TEST_HEX
+    hex "TEST_HEX prompt"
diff --git a/pytest/test_types/config.bool.py b/pytest/test_types/config.bool.py
new file mode 100644
index 0000000..73d1fc0
--- /dev/null
+++ b/pytest/test_types/config.bool.py
@@ -0,0 +1,5 @@
+TEST_BOOL.val = True
+assert TEST_BOOL.val == True
+
+TEST_BOOL.val = False
+assert TEST_BOOL.val == False
diff --git a/pytest/test_types/config.hex.py b/pytest/test_types/config.hex.py
new file mode 100644
index 0000000..47da27b
--- /dev/null
+++ b/pytest/test_types/config.hex.py
@@ -0,0 +1,6 @@
+TEST_HEX.val = 0x80000000
+assert TEST_HEX.val == 0x80000000
+TEST_HEX.val = 0
+assert TEST_HEX.val == 0
+TEST_HEX.val = 0x12345678
+assert TEST_HEX.val == 0x12345678
diff --git a/pytest/test_types/config.int.py b/pytest/test_types/config.int.py
new file mode 100644
index 0000000..17447db
--- /dev/null
+++ b/pytest/test_types/config.int.py
@@ -0,0 +1,10 @@
+TEST_INT.val = -2147483648
+assert TEST_INT.val == -2147483648
+TEST_INT.val = -1
+assert TEST_INT.val == -1
+TEST_INT.val = 0
+assert TEST_INT.val == 0
+TEST_INT.val = 1
+assert TEST_INT.val == 1
+TEST_INT.val = 2147483647
+assert TEST_INT.val == 2147483647
diff --git a/pytest/test_types/config.py b/pytest/test_types/config.py
new file mode 100644
index 0000000..77a0cf4
--- /dev/null
+++ b/pytest/test_types/config.py
@@ -0,0 +1,19 @@
+TEST_BOOL.val = True
+TEST_BOOL.val = False
+
+TEST_TRISTATE.val = False
+TEST_TRISTATE.val = None
+TEST_TRISTATE.val = True
+
+TEST_STRING.val = ""
+TEST_STRING.val = "FOO"
+
+TEST_INT.val = -2147483648
+TEST_INT.val = -1
+TEST_INT.val = 0
+TEST_INT.val = 1
+TEST_INT.val = 2147483647
+
+TEST_HEX.val = 0x80000000
+TEST_HEX.val = 0
+TEST_HEX.val = 0x12345678
diff --git a/pytest/test_types/config.string.py b/pytest/test_types/config.string.py
new file mode 100644
index 0000000..688aea0
--- /dev/null
+++ b/pytest/test_types/config.string.py
@@ -0,0 +1,6 @@
+TEST_STRING.val = ""
+assert TEST_STRING.val == ""
+TEST_STRING.val = "FOO"
+assert TEST_STRING.val == "FOO"
+TEST_STRING.val = "FOO BAR"
+assert TEST_STRING.val == "FOO BAR"
diff --git a/pytest/test_types/config.tristate.py b/pytest/test_types/config.tristate.py
new file mode 100644
index 0000000..add0206
--- /dev/null
+++ b/pytest/test_types/config.tristate.py
@@ -0,0 +1,10 @@
+TEST_TRISTATE.val = False
+assert TEST_TRISTATE.val == False
+
+# Tristates will default to False if nothing sets it to True
+# This means we cannot read None...
+TEST_TRISTATE.val = None
+assert TEST_TRISTATE.val == False
+
+TEST_TRISTATE.val = True
+assert TEST_TRISTATE.val == True
diff --git a/pytest/test_types/fail.config.bool.py b/pytest/test_types/fail.config.bool.py
new file mode 100644
index 0000000..8a32783
--- /dev/null
+++ b/pytest/test_types/fail.config.bool.py
@@ -0,0 +1 @@
+TEST_BOOL.val = "asdf"
diff --git a/pytest/test_types/test_types.py b/pytest/test_types/test_types.py
new file mode 100644
index 0000000..95a1572
--- /dev/null
+++ b/pytest/test_types/test_types.py
@@ -0,0 +1,34 @@
+import os
+import glob
+import kconfiglib
+import pytest
+
+CUR_DIR = os.path.dirname(os.path.realpath(__file__))
+
+@pytest.mark.parametrize("config_file",
+                         sorted(glob.glob(CUR_DIR + '/config*.py',
+                                          recursive=True)))
+def test_configs_should_not_crash(config_file):
+    """Test config files that should not crash.
+
+    No asserts are used as we are just looking for exceptions.
+    """
+    kconfig_path = CUR_DIR + '/Kconfig'
+
+    kconf = kconfiglib.Kconfig(kconfig_path, suppress_traceback=True)
+    kconf.load_config(filename=config_file)
+
+
+@pytest.mark.parametrize("config_file",
+                         sorted(glob.glob(CUR_DIR + '/fail.config*.py',
+                                          recursive=True)))
+def test_configs_should_crash(config_file):
+    """Test config files that should not crash.
+
+    No asserts are used as we are just looking for exceptions.
+    """
+    kconfig_path = CUR_DIR + '/Kconfig'
+
+    kconf = kconfiglib.Kconfig(kconfig_path, warn=False)
+    with pytest.raises(Exception):
+        kconf.load_config(filename=config_file)