Merge pull request #170 from mattpolzin/feature/131/server-var-valida…

…tion

Add validation that all server template variables are defined.

Sources/OpenAPIKit/Server.swift

@@ -41,6 +41,21 @@ extension OpenAPI {
             self.variables = variables
             self.vendorExtensions = vendorExtensions
         }
+
+        /// Create an OpenAPI Server Object with a URL containing
+        /// variables that can change depending on the context in
+        /// which the API is invoked,
+        public init(
+            urlTemplate: URLTemplate,
+            description: String? = nil,
+            variables: OrderedDictionary<String, Variable> = [:],
+            vendorExtensions: [String: AnyCodable] = [:]
+        ) {
+            self.urlTemplate = urlTemplate
+            self.description = description
+            self.variables = variables
+            self.vendorExtensions = vendorExtensions
+        }
     }
 }
 

Sources/OpenAPIKit/Validator/Validation+Builtins.swift

@@ -128,6 +128,29 @@ extension Validation {
         )
     }
 
+    /// Validate that all Server Objects define all of the variables found in their URL Templates.
+    ///
+    /// For example, a server URL Template of `{scheme}://website.com/{path}` would
+    /// fail this validation if either "scheme" or "path" were not found in the Server Object's
+    /// `variables` dictionary.
+    ///
+    /// - Important: This is not an included validation by default.
+    public static var serverVariablesAreDefined: Validation<OpenAPI.Server> {
+        .init(
+            check: { context in
+                let missingVariables = context.subject.urlTemplate.variables
+                    .filter { !context.subject.variables.contains(key: $0) }
+
+                return missingVariables.map { variableName in
+                    ValidationError(
+                        reason: "Server Object does not define the variable '\(variableName)' that is found in the `urlTemplate` '\(context.subject.urlTemplate.rawValue)'",
+                        at: context.codingPath
+                    )
+                }
+            }
+        )
+    }
+
     // MARK: - Included with `Validator()` by default
 
     /// Validate the OpenAPI Document's `Operations` all have at least

Tests/OpenAPIKitTests/Validator/BuiltinValidationTests.swift

@@ -235,6 +235,82 @@ final class BuiltinValidationTests: XCTestCase {
         try document.validate(using: validator)
     }
 
+    func test_missingServerVariableFails() throws {
+        let document = OpenAPI.Document(
+            info: .init(title: "test", version: "1.0"),
+            servers: [
+                .init(urlTemplate: URLTemplate(rawValue: "https://website.com/{path}")!)
+            ],
+            paths: [:],
+            components: .noComponents
+        )
+
+        let validator = Validator.blank.validating(.serverVariablesAreDefined)
+        XCTAssertThrowsError(try document.validate(using: validator)) { error in
+            XCTAssertEqual(
+                (error as? ValidationErrorCollection)?.values.map(String.init(describing:)),
+                [
+                    "Server Object does not define the variable 'path' that is found in the `urlTemplate` 'https://website.com/{path}' at path: .servers[0]"
+                ]
+            )
+        }
+    }
+
+    func test_partialMissingServerVariablesFails() throws {
+        let document = OpenAPI.Document(
+            info: .init(title: "test", version: "1.0"),
+            servers: [
+                .init(
+                    urlTemplate: URLTemplate(rawValue: "{scheme}://website.com/{path}")!,
+                    variables: ["scheme": .init(default: "scheme")]
+                )
+            ],
+            paths: [:],
+            components: .noComponents
+        )
+
+        let validator = Validator.blank.validating(.serverVariablesAreDefined)
+        XCTAssertThrowsError(try document.validate(using: validator)) { error in
+            XCTAssertEqual(
+                (error as? ValidationErrorCollection)?.values.map(String.init(describing:)),
+                [
+                    "Server Object does not define the variable 'path' that is found in the `urlTemplate` '{scheme}://website.com/{path}' at path: .servers[0]"
+                ]
+            )
+        }
+    }
+
+    func test_noSevrerVariablesSucceeds() throws {
+        let document = OpenAPI.Document(
+            info: .init(title: "test", version: "1.0"),
+            servers: [
+                .init(urlTemplate: URLTemplate(rawValue: "https://website.com")!)
+            ],
+            paths: [:],
+            components: .noComponents
+        )
+
+        let validator = Validator.blank.validating(.serverVariablesAreDefined)
+        try document.validate(using: validator)
+    }
+
+    func test_allServerVariablesDefinedSucceeds() throws {
+        let document = OpenAPI.Document(
+            info: .init(title: "test", version: "1.0"),
+            servers: [
+                .init(
+                    urlTemplate: URLTemplate(rawValue: "https://website.com/{path}")!,
+                    variables: ["path": .init(default: "welcome")]
+                )
+            ],
+            paths: [:],
+            components: .noComponents
+        )
+
+        let validator = Validator.blank.validating(.serverVariablesAreDefined)
+        try document.validate(using: validator)
+    }
+
     func test_duplicateTagOnDocumentFails() {
         let document = OpenAPI.Document(
             info: .init(title: "test", version: "1.0"),