test: Verify string format validation end-to-end via OpenApiServer

Add /format/email and /format/byte operations to openapi.json and
openapi.yaml fixtures. Register inline handlers in OpenApiServerIT
and add four IT methods covering valid/invalid email and base64 inputs.

Author: thced

src/test/java/com/retailsvc/http/OpenApiServerIT.java

@@ -599,6 +599,110 @@ void postBlockedForbiddenTokenReturns400() {
     }
   }
 
+  @Nested
+  class FormatEmail {
+
+    String path = "/format/email";
+
+    @Test
+    void formatEmailShouldReturnBadRequestOnInvalidEmail() {
+      try (var server =
+              newServer(Map.of("format-email", exchange -> exchange.sendResponseHeaders(200, -1)));
+          var client = httpClient()) {
+
+        var request = newRequest(server, path + "?addr=not-an-email", "GET", noBody());
+
+        var response = client.send(request, BodyHandlers.ofString());
+        var statusCode = response.statusCode();
+        var contentType = response.headers().firstValue("Content-Type").orElse("");
+        var responseBody = response.body();
+
+        assertThat(statusCode).isEqualTo(400);
+        assertThat(contentType).contains("application/problem+json");
+        assertThat(responseBody).contains("\"format\"");
+
+      } catch (IOException e) {
+        fail(e);
+      } catch (InterruptedException e) {
+        Thread.currentThread().interrupt();
+        fail(e);
+      }
+    }
+
+    @Test
+    void formatEmailShouldReturnOkOnValidEmail() {
+      try (var server =
+              newServer(Map.of("format-email", exchange -> exchange.sendResponseHeaders(200, -1)));
+          var client = httpClient()) {
+
+        var request = newRequest(server, path + "?addr=user%40example.com", "GET", noBody());
+
+        var response = client.send(request, BodyHandlers.ofString());
+        var statusCode = response.statusCode();
+
+        assertThat(statusCode).isEqualTo(200);
+
+      } catch (IOException e) {
+        fail(e);
+      } catch (InterruptedException e) {
+        Thread.currentThread().interrupt();
+        fail(e);
+      }
+    }
+  }
+
+  @Nested
+  class FormatByte {
+
+    String path = "/format/byte";
+
+    @Test
+    void formatByteShouldReturnBadRequestOnInvalidBase64() {
+      try (var server =
+              newServer(Map.of("format-byte", exchange -> exchange.sendResponseHeaders(200, -1)));
+          var client = httpClient()) {
+
+        var request = newRequest(server, path + "?data=not%20base64!!", "GET", noBody());
+
+        var response = client.send(request, BodyHandlers.ofString());
+        var statusCode = response.statusCode();
+        var contentType = response.headers().firstValue("Content-Type").orElse("");
+        var responseBody = response.body();
+
+        assertThat(statusCode).isEqualTo(400);
+        assertThat(contentType).contains("application/problem+json");
+        assertThat(responseBody).contains("\"format\"");
+
+      } catch (IOException e) {
+        fail(e);
+      } catch (InterruptedException e) {
+        Thread.currentThread().interrupt();
+        fail(e);
+      }
+    }
+
+    @Test
+    void formatByteShouldReturnOkOnValidBase64() {
+      try (var server =
+              newServer(Map.of("format-byte", exchange -> exchange.sendResponseHeaders(200, -1)));
+          var client = httpClient()) {
+
+        var request = newRequest(server, path + "?data=aGVsbG8%3D", "GET", noBody());
+
+        var response = client.send(request, BodyHandlers.ofString());
+        var statusCode = response.statusCode();
+
+        assertThat(statusCode).isEqualTo(200);
+
+      } catch (IOException e) {
+        fail(e);
+      } catch (InterruptedException e) {
+        Thread.currentThread().interrupt();
+        fail(e);
+      }
+    }
+  }
+
   @Nested
   class Gates {
 

src/test/resources/openapi.json

@@ -251,6 +251,48 @@
         "responses": { "200": { "description": "OK" } }
       }
     },
+    "/format/email": {
+      "get": {
+        "operationId": "format-email",
+        "parameters": [
+          {
+            "in": "query",
+            "name": "addr",
+            "required": true,
+            "schema": {
+              "type": "string",
+              "format": "email"
+            }
+          }
+        ],
+        "responses": {
+          "200": {
+            "description": "OK"
+          }
+        }
+      }
+    },
+    "/format/byte": {
+      "get": {
+        "operationId": "format-byte",
+        "parameters": [
+          {
+            "in": "query",
+            "name": "data",
+            "required": true,
+            "schema": {
+              "type": "string",
+              "format": "byte"
+            }
+          }
+        ],
+        "responses": {
+          "200": {
+            "description": "OK"
+          }
+        }
+      }
+    },
     "/gates": {
       "post": {
         "operationId": "post-gate",

src/test/resources/openapi.yaml

@@ -177,6 +177,34 @@ paths:
         "200":
           description: OK
 
+  /format/email:
+    get:
+      operationId: format-email
+      parameters:
+        - in: query
+          name: addr
+          required: true
+          schema:
+            type: string
+            format: email
+      responses:
+        "200":
+          description: OK
+
+  /format/byte:
+    get:
+      operationId: format-byte
+      parameters:
+        - in: query
+          name: data
+          required: true
+          schema:
+            type: string
+            format: byte
+      responses:
+        "200":
+          description: OK
+
   /gates:
     post:
       operationId: post-gate