scripts: tests: sanitycheck: Add testcases for schema validation.

test_sanitycheck.py: Add testcases for correct & incorrect
testcase/platform yaml schemas.

Signed-off-by: Aastha Grover <aastha.grover@intel.com>

scripts/tests/sanitycheck/test_data/platform_correct_schema.yaml

@@ -0,0 +1,4 @@
+testing:
+  ignore_tags:
+    - correct_schema_1
+    - correct_schema_2

scripts/tests/sanitycheck/test_data/platform_incorrect_schema.yaml

@@ -0,0 +1,4 @@
+test:
+  ignore_tags:
+    - incorrect_schema_1
+    - incorrect_schema_2

scripts/tests/sanitycheck/test_data/testcase_incorrect_schema.yaml

@@ -0,0 +1,4 @@
+test:
+  testing.incorrect_schema:
+    tag: demo incorrect_tag
+    platform_exclude: demo_board_1

scripts/tests/sanitycheck/test_sanitycheck.py

@@ -0,0 +1,47 @@
+#!/usr/bin/env python3
+# Copyright (c) 2020 Intel Corporation
+#
+# SPDX-License-Identifier: Apache-2.0
+"""
+This test file contains foundational testcases for Sanitycheck tool
+"""
+
+import os
+import sys
+import pytest
+
+ZEPHYR_BASE = os.getenv("ZEPHYR_BASE")
+sys.path.insert(0, os.path.join(ZEPHYR_BASE, "scripts/sanity_chk"))
+
+import scl
+from sanitylib import SanityConfigParser
+
+def test_yamlload():
+    """ Test to check if loading the non-existent files raises the errors """
+    filename = 'testcase_nc.yaml'
+    with pytest.raises(FileNotFoundError):
+        scl.yaml_load(filename)
+
+
+@pytest.mark.parametrize("filename, schema",
+                         [("testcase_correct_schema.yaml", "testcase-schema.yaml"),
+                          ("platform_correct_schema.yaml", "platform-schema.yaml")])
+def test_correct_schema(filename, schema, test_data):
+    """ Test to validate the testcase schema"""
+    filename = test_data + filename
+    schema = scl.yaml_load(ZEPHYR_BASE +'/scripts/sanity_chk/' + schema)
+    data = SanityConfigParser(filename, schema)
+    data.load()
+    assert data
+
+
+@pytest.mark.parametrize("filename, schema",
+                         [("testcase_incorrect_schema.yaml", "testcase-schema.yaml"),
+                          ("platform_incorrect_schema.yaml", "platform-schema.yaml")])
+def test_incorrect_schema(filename, schema, test_data):
+    """ Test to validate the exception is raised for incorrect testcase schema"""
+    filename = test_data + filename
+    schema = scl.yaml_load(ZEPHYR_BASE +'/scripts/sanity_chk/' + schema)
+    with pytest.raises(Exception) as exception:
+        scl.yaml_load_verify(filename, schema)
+        assert str(exception.value) == "Schema validation failed"