Do not include identical response bodies; only use example key if size > 1

Author: sksamuel

src/main/kotlin/io/kotest/extensions/ktor/openapi/OpenApiBuilder.kt

@@ -77,11 +77,16 @@ class OpenApiBuilder(private val config: OpenApiConfig) {
 
                      // for each content type that is the same, they are added as multiple examples
                      // to the same MediaType in the response content
-                     tracesByContentType.withIndex().forEach { (index, value) ->
-                        mediaType.addExamples(
-                           "Example ${index + 1}",
-                           Example().value(value.responseBody)
-                        )
+                     val bodies = tracesByContentType.mapNotNull { it.responseBody }.distinct()
+                     if (bodies.size == 1) {
+                        mediaType.example = bodies.first()
+                     } else if (bodies.size > 1) {
+                        bodies.withIndex().forEach { (index, value) ->
+                           mediaType.addExamples(
+                              "Example ${index + 1}",
+                              Example().value(value)
+                           )
+                        }
                      }
 
                      if (resp.content == null) resp.content = Content()

src/test/kotlin/io/kotest/extensions/ktor/openapi/OpenApiWriterTest.kt

@@ -2,6 +2,7 @@ package io.kotest.extensions.ktor.openapi
 
 import io.kotest.core.spec.style.FunSpec
 import io.kotest.matchers.string.shouldInclude
+import io.kotest.matchers.string.shouldNotInclude
 import io.ktor.http.ContentType
 import io.ktor.http.HttpMethod
 import io.ktor.http.HttpStatusCode
@@ -114,4 +115,56 @@ class OpenApiWriterTest : FunSpec({
       file.readText() shouldInclude "beam me up scotty"
       file.readText() shouldInclude "text/css"
    }
+
+   test("builder should not set example key if only one response") {
+      val file = Files.createTempFile("openapi", "test")
+      val builder = OpenApiBuilder(OpenApiConfig(path = file))
+      builder.addTraces(
+         "parth path",
+         listOf(
+            Trace.default(HttpMethod.Get, "parth path")
+               .copy(
+                  responseBody = "beam me up scotty",
+                  contentType = ContentType.Text.CSS,
+                  status = HttpStatusCode.MovedPermanently,
+               )
+         )
+      )
+      OpenApiWriter(file).write(builder)
+      file.readText() shouldInclude "beam me up scotty"
+      file.readText() shouldNotInclude "Example 1"
+   }
+
+   test("builder should not include identical response bodies") {
+      val file = Files.createTempFile("openapi", "test")
+      val builder = OpenApiBuilder(OpenApiConfig(path = file))
+      builder.addTraces(
+         "parth path",
+         listOf(
+            Trace.default(HttpMethod.Get, "parth path")
+               .copy(
+                  responseBody = "beam me up scotty",
+                  contentType = ContentType.Text.CSS,
+                  status = HttpStatusCode.MovedPermanently,
+               ),
+            Trace.default(HttpMethod.Get, "parth path")
+               .copy(
+                  responseBody = "beam me up jimmy",
+                  contentType = ContentType.Text.CSS,
+                  status = HttpStatusCode.MovedPermanently,
+               ),
+            Trace.default(HttpMethod.Get, "parth path")
+               .copy(
+                  responseBody = "beam me up scotty",
+                  contentType = ContentType.Text.CSS,
+                  status = HttpStatusCode.MovedPermanently,
+               )
+         )
+      )
+      OpenApiWriter(file).write(builder)
+      file.readText() shouldInclude "beam me up scotty"
+      file.readText() shouldInclude "Example 1"
+      file.readText() shouldInclude "Example 2"
+      file.readText() shouldNotInclude "Example 3"
+   }
 })