spec: add specs for PolicyConfigValidator

spec/policy_config_validator_spec.lua

@@ -0,0 +1,58 @@
+local cjson = require('cjson')
+local policy_config_validator = require('apicast.policy_config_validator')
+
+describe('policy_config_validator', function()
+  -- We use the echo policy schema as an example for the tests.
+  local test_config_schema = cjson.decode([[
+    {
+      "type": "object",
+      "properties": {
+        "status": {
+          "description": "HTTP status code to be returned",
+          "type": "integer"
+        },
+        "exit": {
+          "description": "Exit mode",
+          "type": "string",
+          "oneOf": [{
+              "enum": ["request"],
+              "description": "Interrupts the processing of the request."
+            },
+            {
+              "enum": ["set"],
+              "description": "Only skips the rewrite phase."
+            }
+          ]
+        }
+      }
+    }
+  ]])
+
+  it('returns true with a config that conforms with the schema', function()
+    local valid_config = { status = 200, exit = "request" }
+
+    local is_valid, err = policy_config_validator.validate_config(
+      valid_config, test_config_schema)
+
+    assert.is_true(is_valid)
+    assert.is_nil(err)
+  end)
+
+  it('returns false with a config that does not conform with the schema', function()
+    local invalid_config = { status = "not_an_integer" }
+
+    local is_valid, err = policy_config_validator.validate_config(
+      invalid_config, test_config_schema)
+
+    assert.is_false(is_valid)
+    assert.is_not_nil(err)
+  end)
+
+  it('returns true when the schema is empty', function()
+    assert.is_true(policy_config_validator.validate_config({ a_param = 1 }, {}))
+  end)
+
+  it('returns true when the schema is nil', function()
+    assert.is_true(policy_config_validator.validate_config({ a_param = 1 }, nil))
+  end)
+end)