Add property names assertion

Author: Oleg

src/commonMain/kotlin/smirnov/oleg/json/schema/internal/SchemaLoader.kt

@@ -24,6 +24,7 @@ import smirnov.oleg.json.schema.internal.factories.number.MultipleOfAssertionFac
 import smirnov.oleg.json.schema.internal.factories.`object`.MaxPropertiesAssertionFactory
 import smirnov.oleg.json.schema.internal.factories.`object`.MinPropertiesAssertionFactory
 import smirnov.oleg.json.schema.internal.factories.`object`.PropertiesAssertionFactory
+import smirnov.oleg.json.schema.internal.factories.`object`.PropertyNamesAssertionFactory
 import smirnov.oleg.json.schema.internal.factories.`object`.RequiredAssertionFactory
 import smirnov.oleg.json.schema.internal.factories.string.MaxLengthAssertionFactory
 import smirnov.oleg.json.schema.internal.factories.string.MinLengthAssertionFactory
@@ -50,6 +51,7 @@ private val factories: List<AssertionFactory> = listOf(
   MinPropertiesAssertionFactory,
   RequiredAssertionFactory,
   PropertiesAssertionFactory,
+  PropertyNamesAssertionFactory,
 )
 
 class SchemaLoader {

src/commonMain/kotlin/smirnov/oleg/json/schema/internal/factories/object/PropertyNamesAssertion.kt

@@ -0,0 +1,41 @@
+package smirnov.oleg.json.schema.internal.factories.`object`
+
+import kotlinx.serialization.json.JsonElement
+import kotlinx.serialization.json.JsonObject
+import kotlinx.serialization.json.JsonPrimitive
+import smirnov.oleg.json.schema.ErrorCollector
+import smirnov.oleg.json.schema.internal.AssertionContext
+import smirnov.oleg.json.schema.internal.JsonSchemaAssertion
+import smirnov.oleg.json.schema.internal.LoadingContext
+import smirnov.oleg.json.schema.internal.factories.AbstractAssertionFactory
+
+@Suppress("unused")
+internal object PropertyNamesAssertionFactory : AbstractAssertionFactory("propertyNames") {
+  override fun createFromProperty(element: JsonElement, context: LoadingContext): JsonSchemaAssertion {
+    require(context.isJsonSchema(element)) { "$property must be a valid JSON schema" }
+    val propertyNamesAssertion = context.schemaFrom(element)
+    return PropertyNamesAssertion(propertyNamesAssertion)
+  }
+}
+
+private class PropertyNamesAssertion(
+  private val namesAssertion: JsonSchemaAssertion,
+) : JsonSchemaAssertion {
+  override fun validate(element: JsonElement, context: AssertionContext, errorCollector: ErrorCollector): Boolean {
+    if (element !is JsonObject) {
+      return true
+    }
+    var valid = true
+    element.keys.forEach { property ->
+      val res = namesAssertion.validate(
+        JsonPrimitive(property),
+        context.at(property),
+      ) {
+        errorCollector.onError(it.copy(message = "property $property: ${it.message}"))
+      }
+      valid = valid and res
+    }
+    return valid
+  }
+
+}

src/commonTest/kotlin/smirnov/oleg/json/schema/assertions/object/JsonSchemaPropertyNamesValidationTest.kt

@@ -0,0 +1,73 @@
+package smirnov.oleg.json.schema.assertions.`object`
+
+import io.kotest.assertions.asClue
+import io.kotest.core.spec.style.FunSpec
+import io.kotest.matchers.collections.shouldContainExactly
+import io.kotest.matchers.collections.shouldHaveSize
+import io.kotest.matchers.shouldBe
+import kotlinx.serialization.json.JsonPrimitive
+import kotlinx.serialization.json.buildJsonObject
+import smirnov.oleg.json.pointer.JsonPointer
+import smirnov.oleg.json.schema.JsonSchema
+import smirnov.oleg.json.schema.KEY
+import smirnov.oleg.json.schema.ValidationError
+
+@Suppress("unused")
+class JsonSchemaPropertyNamesValidationTest : FunSpec() {
+  init {
+    JsonSchema.fromDescription(
+      """
+      {
+        "${KEY}schema": "http://json-schema.org/draft-07/schema#",
+        "propertyNames": {
+          "minLength": 3,
+          "maxLength": 5
+        }
+      }
+      """.trimIndent()
+    ).also { schema ->
+      test("object properties passes validation") {
+        val jsonObject = buildJsonObject {
+          put("abc", JsonPrimitive(42))
+          put("abcd", JsonPrimitive(42))
+          put("abcde", JsonPrimitive(42))
+        }
+        val errors = mutableListOf<ValidationError>()
+        val valid = schema.validate(jsonObject, errors::add)
+        jsonObject.asClue {
+          valid shouldBe true
+          errors shouldHaveSize 0
+        }
+      }
+
+      test("object properties fails validation") {
+        val jsonObject = buildJsonObject {
+          put("ab", JsonPrimitive("42"))
+          put("abc", JsonPrimitive(42))
+          put("abcd", JsonPrimitive(42.0))
+          put("abcde", JsonPrimitive(42))
+          put("abcdef", JsonPrimitive(42))
+        }
+        val errors = mutableListOf<ValidationError>()
+        val valid = schema.validate(jsonObject, errors::add)
+        jsonObject.asClue {
+          valid shouldBe false
+          errors.shouldContainExactly(
+            ValidationError(
+              schemaPath = JsonPointer("/propertyNames/minLength"),
+              objectPath = JsonPointer("/ab"),
+              message = "property ab: string length (2) must be greater or equal to 3",
+            ),
+            ValidationError(
+              schemaPath = JsonPointer("/propertyNames/maxLength"),
+              objectPath = JsonPointer("/abcdef"),
+              message = "property abcdef: string length (6) must be less or equal to 5",
+            )
+          )
+        }
+      }
+
+      notAnObjectPasses(schema)
+    }
+  }
+}