From d1e7376cd409449ae0bf5bf32441bb0fd5379f92 Mon Sep 17 00:00:00 2001
From: Maksym Ochenashko <maxochenashko@gmail.com>
Date: Tue, 3 Oct 2023 21:00:55 +0300
Subject: [PATCH 1/4] core-common and sdk-common: Add `Hash` and `Show`
 instances

---
 build.sbt                                     |  4 +-
 .../org/typelevel/otel4s/Attribute.scala      |  8 ++-
 .../org/typelevel/otel4s/AttributeKey.scala   |  3 +
 .../org/typelevel/otel4s/AttributeType.scala  |  3 +
 .../org/typelevel/otel4s/trace/SpanKind.scala |  6 ++
 .../org/typelevel/otel4s/trace/Status.scala   |  6 ++
 .../otel4s/trace/SpanKindSuite.scala          | 66 +++++++++++++++++++
 .../typelevel/otel4s/trace/StatusSuite.scala  | 52 +++++++++++++++
 .../org/typelevel/otel4s/sdk/Attributes.scala | 15 +++++
 .../org/typelevel/otel4s/sdk/Resource.scala   | 17 +++--
 .../sdk/trace/samplers/SamplingDecision.scala | 10 +++
 .../samplers/SamplingDecisionSuite.scala      | 56 ++++++++++++++--
 12 files changed, 231 insertions(+), 15 deletions(-)
 create mode 100644 core/trace/src/test/scala/org/typelevel/otel4s/trace/SpanKindSuite.scala
 create mode 100644 core/trace/src/test/scala/org/typelevel/otel4s/trace/StatusSuite.scala

diff --git a/build.sbt b/build.sbt
index d7629c216..bc9d98657 100644
--- a/build.sbt
+++ b/build.sbt
@@ -120,7 +120,8 @@ lazy val `core-trace` = crossProject(JVMPlatform, JSPlatform, NativePlatform)
     name := "otel4s-core-trace",
     libraryDependencies ++= Seq(
       "org.typelevel" %%% "cats-effect-kernel" % CatsEffectVersion,
-      "org.scodec" %%% "scodec-bits" % ScodecVersion
+      "org.scodec" %%% "scodec-bits" % ScodecVersion,
+      "org.scalameta" %%% "munit-scalacheck" % MUnitVersion % Test
     )
   )
   .settings(scalafixSettings)
@@ -169,6 +170,7 @@ lazy val `sdk-trace` = crossProject(JVMPlatform, JSPlatform, NativePlatform)
     name := "otel4s-sdk-trace",
     libraryDependencies ++= Seq(
       "org.typelevel" %%% "cats-effect" % CatsEffectVersion,
+      "org.scalameta" %%% "munit-scalacheck" % MUnitVersion % Test
     ),
   )
   .settings(munitDependencies)
diff --git a/core/common/src/main/scala/org/typelevel/otel4s/Attribute.scala b/core/common/src/main/scala/org/typelevel/otel4s/Attribute.scala
index e070f8789..e28b3ac87 100644
--- a/core/common/src/main/scala/org/typelevel/otel4s/Attribute.scala
+++ b/core/common/src/main/scala/org/typelevel/otel4s/Attribute.scala
@@ -16,9 +16,9 @@
 
 package org.typelevel.otel4s
 
+import cats.Hash
 import cats.Show
-import cats.implicits.showInterpolator
-import cats.kernel.Hash
+import cats.syntax.show._
 
 /** Represents the key-value attribute.
   *
@@ -76,4 +76,8 @@ String, Boolean, Long, Double, List[String], List[Boolean], List[Long], List[Dou
   implicit def hashAttribute[T: Hash]: Hash[Attribute[T]] =
     Hash.by(a => (a.key, a.value))
 
+  implicit val hashAnyAttribute: Hash[Attribute[_]] = {
+    implicit val hashAny: Hash[Any] = Hash.fromUniversalHashCode
+    Hash.by(a => (a.key, a.value))
+  }
 }
diff --git a/core/common/src/main/scala/org/typelevel/otel4s/AttributeKey.scala b/core/common/src/main/scala/org/typelevel/otel4s/AttributeKey.scala
index f0a770d28..844031f41 100644
--- a/core/common/src/main/scala/org/typelevel/otel4s/AttributeKey.scala
+++ b/core/common/src/main/scala/org/typelevel/otel4s/AttributeKey.scala
@@ -80,4 +80,7 @@ object AttributeKey {
   implicit def attributeKeyShow[A]: Show[AttributeKey[A]] =
     Show.show(key => show"${key.`type`}(${key.name})")
 
+  implicit val attributeKeyAnyHash: Hash[AttributeKey[_]] =
+    Hash.by(key => (key.name, key.`type`))
+
 }
diff --git a/core/common/src/main/scala/org/typelevel/otel4s/AttributeType.scala b/core/common/src/main/scala/org/typelevel/otel4s/AttributeType.scala
index 4b8ddad36..989b3eeac 100644
--- a/core/common/src/main/scala/org/typelevel/otel4s/AttributeType.scala
+++ b/core/common/src/main/scala/org/typelevel/otel4s/AttributeType.scala
@@ -41,4 +41,7 @@ object AttributeType {
   implicit def attributeTypeShow[A]: Show[AttributeType[A]] =
     Show.fromToString
 
+  implicit val attributeTypeAnyHash: Hash[AttributeType[_]] =
+    Hash.fromUniversalHashCode
+
 }
diff --git a/core/trace/src/main/scala/org/typelevel/otel4s/trace/SpanKind.scala b/core/trace/src/main/scala/org/typelevel/otel4s/trace/SpanKind.scala
index a62eb001d..f0b4cdc7a 100644
--- a/core/trace/src/main/scala/org/typelevel/otel4s/trace/SpanKind.scala
+++ b/core/trace/src/main/scala/org/typelevel/otel4s/trace/SpanKind.scala
@@ -17,6 +17,9 @@
 package org.typelevel.otel4s
 package trace
 
+import cats.Hash
+import cats.Show
+
 /** Type of [[Span]]. Can be used to specify additional relationships between
   * spans in addition to a parent/child relationship.
   */
@@ -48,4 +51,7 @@ object SpanKind {
     * relationship between producer and consumer spans.
     */
   case object Consumer extends SpanKind
+
+  implicit val spanKindHash: Hash[SpanKind] = Hash.fromUniversalHashCode
+  implicit val spanKindShow: Show[SpanKind] = Show.fromToString
 }
diff --git a/core/trace/src/main/scala/org/typelevel/otel4s/trace/Status.scala b/core/trace/src/main/scala/org/typelevel/otel4s/trace/Status.scala
index 9b7e03715..d11d73641 100644
--- a/core/trace/src/main/scala/org/typelevel/otel4s/trace/Status.scala
+++ b/core/trace/src/main/scala/org/typelevel/otel4s/trace/Status.scala
@@ -16,6 +16,9 @@
 
 package org.typelevel.otel4s.trace
 
+import cats.Hash
+import cats.Show
+
 /** The set of canonical status codes
   */
 sealed trait Status extends Product with Serializable
@@ -33,4 +36,7 @@ object Status {
   /** The operation contains an error. */
   case object Error extends Status
 
+  implicit val statusHash: Hash[Status] = Hash.fromUniversalHashCode
+  implicit val statusShow: Show[Status] = Show.fromToString
+
 }
diff --git a/core/trace/src/test/scala/org/typelevel/otel4s/trace/SpanKindSuite.scala b/core/trace/src/test/scala/org/typelevel/otel4s/trace/SpanKindSuite.scala
new file mode 100644
index 000000000..1dc03bcd8
--- /dev/null
+++ b/core/trace/src/test/scala/org/typelevel/otel4s/trace/SpanKindSuite.scala
@@ -0,0 +1,66 @@
+/*
+ * Copyright 2022 Typelevel
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.typelevel.otel4s.trace
+
+import cats.Hash
+import cats.Show
+import munit._
+import org.scalacheck.Gen
+import org.scalacheck.Prop
+
+class SpanKindSuite extends ScalaCheckSuite {
+
+  private val spanKindGen: Gen[SpanKind] =
+    Gen.oneOf(
+      SpanKind.Internal,
+      SpanKind.Server,
+      SpanKind.Client,
+      SpanKind.Producer,
+      SpanKind.Consumer
+    )
+
+  property("Show[SpanKind]") {
+    Prop.forAll(spanKindGen) { spanKind =>
+      val expected = spanKind match {
+        case SpanKind.Internal => "Internal"
+        case SpanKind.Server   => "Server"
+        case SpanKind.Client   => "Client"
+        case SpanKind.Producer => "Producer"
+        case SpanKind.Consumer => "Consumer"
+      }
+
+      assertEquals(Show[SpanKind].show(spanKind), expected)
+    }
+  }
+
+  test("Hash[SpanKind]") {
+    val allWithIndex = List(
+      SpanKind.Internal,
+      SpanKind.Server,
+      SpanKind.Client,
+      SpanKind.Producer,
+      SpanKind.Consumer
+    ).zipWithIndex
+
+    allWithIndex.foreach { case (that, thatIdx) =>
+      allWithIndex.foreach { case (other, otherIdx) =>
+        assertEquals(Hash[SpanKind].eqv(that, other), thatIdx == otherIdx)
+      }
+    }
+  }
+
+}
diff --git a/core/trace/src/test/scala/org/typelevel/otel4s/trace/StatusSuite.scala b/core/trace/src/test/scala/org/typelevel/otel4s/trace/StatusSuite.scala
new file mode 100644
index 000000000..a97bfd249
--- /dev/null
+++ b/core/trace/src/test/scala/org/typelevel/otel4s/trace/StatusSuite.scala
@@ -0,0 +1,52 @@
+/*
+ * Copyright 2022 Typelevel
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.typelevel.otel4s.trace
+
+import cats.Hash
+import cats.Show
+import munit._
+import org.scalacheck.Gen
+import org.scalacheck.Prop
+
+class StatusSuite extends ScalaCheckSuite {
+
+  private val statusGen: Gen[Status] =
+    Gen.oneOf(Status.Unset, Status.Ok, Status.Error)
+
+  property("Show[Status]") {
+    Prop.forAll(statusGen) { status =>
+      val expected = status match {
+        case Status.Unset => "Unset"
+        case Status.Ok    => "Ok"
+        case Status.Error => "Error"
+      }
+
+      assertEquals(Show[Status].show(status), expected)
+    }
+  }
+
+  test("Hash[Status]") {
+    val allWithIndex = List(Status.Unset, Status.Ok, Status.Error).zipWithIndex
+
+    allWithIndex.foreach { case (that, thatIdx) =>
+      allWithIndex.foreach { case (other, otherIdx) =>
+        assertEquals(Hash[Status].eqv(that, other), thatIdx == otherIdx)
+      }
+    }
+  }
+
+}
diff --git a/sdk/common/src/main/scala/org/typelevel/otel4s/sdk/Attributes.scala b/sdk/common/src/main/scala/org/typelevel/otel4s/sdk/Attributes.scala
index b2a3a3d83..d28871612 100644
--- a/sdk/common/src/main/scala/org/typelevel/otel4s/sdk/Attributes.scala
+++ b/sdk/common/src/main/scala/org/typelevel/otel4s/sdk/Attributes.scala
@@ -17,6 +17,7 @@
 package org.typelevel.otel4s.sdk
 
 import cats.Applicative
+import cats.Hash
 import cats.Monad
 import cats.Monoid
 import cats.Show
@@ -59,6 +60,17 @@ final class Attributes private (
   def toMap: Map[AttributeKey[_], Attribute[_]] = m
   def toList: List[Attribute[_]] = m.values.toList
 
+  override def hashCode(): Int =
+    Hash[Attributes].hash(this)
+
+  override def equals(obj: Any): Boolean =
+    obj match {
+      case other: Attributes => Hash[Attributes].eqv(this, other)
+      case _                 => false
+    }
+
+  override def toString: String =
+    Show[Attributes].show(this)
 }
 
 object Attributes {
@@ -79,6 +91,9 @@ object Attributes {
       .mkString("Attributes(", ", ", ")")
   }
 
+  implicit val hashAttributes: Hash[Attributes] =
+    Hash.by(_.m)
+
   implicit val monoidAttributes: Monoid[Attributes] =
     new Monoid[Attributes] {
       def empty: Attributes = Attributes.Empty
diff --git a/sdk/common/src/main/scala/org/typelevel/otel4s/sdk/Resource.scala b/sdk/common/src/main/scala/org/typelevel/otel4s/sdk/Resource.scala
index 0e7912f68..d4d071bf5 100644
--- a/sdk/common/src/main/scala/org/typelevel/otel4s/sdk/Resource.scala
+++ b/sdk/common/src/main/scala/org/typelevel/otel4s/sdk/Resource.scala
@@ -16,11 +16,12 @@
 
 package org.typelevel.otel4s.sdk
 
+import cats.Hash
 import cats.Show
-import cats.implicits.catsSyntaxEitherId
-import cats.implicits.catsSyntaxOptionId
-import cats.implicits.catsSyntaxSemigroup
-import cats.implicits.showInterpolator
+import cats.syntax.either._
+import cats.syntax.option._
+import cats.syntax.semigroup._
+import cats.syntax.show._
 import org.typelevel.otel4s.Attribute
 import org.typelevel.otel4s.sdk.Resource.ResourceInitiationError
 import org.typelevel.otel4s.semconv.resource.attributes.ResourceAttributes._
@@ -76,6 +77,9 @@ final case class Resource(
       throw _,
       identity
     )
+
+  override def toString: String =
+    Show[Resource].show(this)
 }
 
 object Resource {
@@ -119,6 +123,9 @@ object Resource {
   val Default: Resource = TelemetrySdk.mergeIntoUnsafe(Mandatory)
 
   implicit val showResource: Show[Resource] =
-    r => show"Resource(${r.attributes}, ${r.schemaUrl})"
+    r => show"Resource{attributes=${r.attributes}, schemaUrl=${r.schemaUrl}}"
+
+  implicit val hashResource: Hash[Resource] =
+    Hash.by(r => (r.attributes, r.schemaUrl))
 
 }
diff --git a/sdk/trace/src/main/scala/org/typelevel/otel4s/sdk/trace/samplers/SamplingDecision.scala b/sdk/trace/src/main/scala/org/typelevel/otel4s/sdk/trace/samplers/SamplingDecision.scala
index 9cb01c4d0..4f3ef6c08 100644
--- a/sdk/trace/src/main/scala/org/typelevel/otel4s/sdk/trace/samplers/SamplingDecision.scala
+++ b/sdk/trace/src/main/scala/org/typelevel/otel4s/sdk/trace/samplers/SamplingDecision.scala
@@ -16,6 +16,9 @@
 
 package org.typelevel.otel4s.sdk.trace.samplers
 
+import cats.Hash
+import cats.Show
+
 /** A decision on whether a span should be recorded, sampled, or dropped.
   */
 sealed abstract class SamplingDecision(val isSampled: Boolean)
@@ -35,4 +38,11 @@ object SamplingDecision {
   /** The span is recorded, and the Sampled flag will be set.
     */
   case object RecordAndSample extends SamplingDecision(true)
+
+  implicit val samplingDecisionHash: Hash[SamplingDecision] =
+    Hash.fromUniversalHashCode
+
+  implicit val samplingDecisionShow: Show[SamplingDecision] =
+    Show.fromToString
+
 }
diff --git a/sdk/trace/src/test/scala/org/typelevel/otel4s/sdk/trace/samplers/SamplingDecisionSuite.scala b/sdk/trace/src/test/scala/org/typelevel/otel4s/sdk/trace/samplers/SamplingDecisionSuite.scala
index ddb703162..8f8ba3b5c 100644
--- a/sdk/trace/src/test/scala/org/typelevel/otel4s/sdk/trace/samplers/SamplingDecisionSuite.scala
+++ b/sdk/trace/src/test/scala/org/typelevel/otel4s/sdk/trace/samplers/SamplingDecisionSuite.scala
@@ -16,18 +16,60 @@
 
 package org.typelevel.otel4s.sdk.trace.samplers
 
+import cats.Hash
+import cats.Show
 import munit._
+import org.scalacheck.Gen
+import org.scalacheck.Prop
 
-class SamplingDecisionSuite extends FunSuite {
-  test("Drop should have isSampled = false") {
-    assertEquals(SamplingDecision.Drop.isSampled, false)
+class SamplingDecisionSuite extends ScalaCheckSuite {
+
+  private val samplingDecisionGen: Gen[SamplingDecision] =
+    Gen.oneOf(
+      SamplingDecision.Drop,
+      SamplingDecision.RecordOnly,
+      SamplingDecision.RecordAndSample
+    )
+
+  property("is sampled") {
+    Prop.forAll(samplingDecisionGen) { decision =>
+      val expected = decision match {
+        case SamplingDecision.Drop            => false
+        case SamplingDecision.RecordOnly      => false
+        case SamplingDecision.RecordAndSample => true
+      }
+
+      assertEquals(decision.isSampled, expected)
+    }
   }
 
-  test("RecordOnly should have isSampled = false") {
-    assertEquals(SamplingDecision.RecordOnly.isSampled, false)
+  property("Show[SamplingDecision]") {
+    Prop.forAll(samplingDecisionGen) { decision =>
+      val expected = decision match {
+        case SamplingDecision.Drop            => "Drop"
+        case SamplingDecision.RecordOnly      => "RecordOnly"
+        case SamplingDecision.RecordAndSample => "RecordAndSample"
+      }
+
+      assertEquals(Show[SamplingDecision].show(decision), expected)
+    }
   }
 
-  test("RecordAndSample should have isSampled = true") {
-    assertEquals(SamplingDecision.RecordAndSample.isSampled, true)
+  test("Hash[SamplingDecision]") {
+    val allWithIndex = List(
+      SamplingDecision.Drop,
+      SamplingDecision.RecordOnly,
+      SamplingDecision.RecordAndSample
+    ).zipWithIndex
+
+    allWithIndex.foreach { case (that, thatIdx) =>
+      allWithIndex.foreach { case (other, otherIdx) =>
+        assertEquals(
+          Hash[SamplingDecision].eqv(that, other),
+          thatIdx == otherIdx
+        )
+      }
+    }
   }
+
 }

From 282da326053615dd99d9d4aa533f5ddceb1942c8 Mon Sep 17 00:00:00 2001
From: Maksym Ochenashko <maxochenashko@gmail.com>
Date: Wed, 4 Oct 2023 09:56:47 +0300
Subject: [PATCH 2/4] Use cats-discipline to test `Hash` laws

---
 build.sbt                                     |  8 +++-
 .../org/typelevel/otel4s/Attribute.scala      |  2 +-
 .../org/typelevel/otel4s/AttributeKey.scala   |  2 +-
 .../org/typelevel/otel4s/AttributeType.scala  |  2 +-
 .../otel4s/trace/SpanKindSuite.scala          | 30 ++++++--------
 .../typelevel/otel4s/trace/StatusSuite.scala  | 24 +++++------
 .../otel4s/trace/TraceFlagsSuite.scala        | 25 +++++++++++-
 .../otel4s/sdk/ArbitraryInstances.scala       | 40 +++++++++++++++++++
 .../otel4s/sdk/AttributesLawTests.scala       | 13 ++----
 .../samplers/SamplingDecisionSuite.scala      | 31 ++++++--------
 10 files changed, 112 insertions(+), 65 deletions(-)

diff --git a/build.sbt b/build.sbt
index bc9d98657..8355d0239 100644
--- a/build.sbt
+++ b/build.sbt
@@ -121,7 +121,9 @@ lazy val `core-trace` = crossProject(JVMPlatform, JSPlatform, NativePlatform)
     libraryDependencies ++= Seq(
       "org.typelevel" %%% "cats-effect-kernel" % CatsEffectVersion,
       "org.scodec" %%% "scodec-bits" % ScodecVersion,
-      "org.scalameta" %%% "munit-scalacheck" % MUnitVersion % Test
+      "org.scalameta" %%% "munit-scalacheck" % MUnitVersion % Test,
+      "org.typelevel" %%% "cats-laws" % CatsVersion % Test,
+      "org.typelevel" %%% "discipline-munit" % DisciplineMUnitVersion % Test
     )
   )
   .settings(scalafixSettings)
@@ -170,7 +172,9 @@ lazy val `sdk-trace` = crossProject(JVMPlatform, JSPlatform, NativePlatform)
     name := "otel4s-sdk-trace",
     libraryDependencies ++= Seq(
       "org.typelevel" %%% "cats-effect" % CatsEffectVersion,
-      "org.scalameta" %%% "munit-scalacheck" % MUnitVersion % Test
+      "org.scalameta" %%% "munit-scalacheck" % MUnitVersion % Test,
+      "org.typelevel" %%% "cats-laws" % CatsVersion % Test,
+      "org.typelevel" %%% "discipline-munit" % DisciplineMUnitVersion % Test
     ),
   )
   .settings(munitDependencies)
diff --git a/core/common/src/main/scala/org/typelevel/otel4s/Attribute.scala b/core/common/src/main/scala/org/typelevel/otel4s/Attribute.scala
index e28b3ac87..ad386f4a5 100644
--- a/core/common/src/main/scala/org/typelevel/otel4s/Attribute.scala
+++ b/core/common/src/main/scala/org/typelevel/otel4s/Attribute.scala
@@ -76,7 +76,7 @@ String, Boolean, Long, Double, List[String], List[Boolean], List[Long], List[Dou
   implicit def hashAttribute[T: Hash]: Hash[Attribute[T]] =
     Hash.by(a => (a.key, a.value))
 
-  implicit val hashAnyAttribute: Hash[Attribute[_]] = {
+  implicit val hashAttributeExistential: Hash[Attribute[_]] = {
     implicit val hashAny: Hash[Any] = Hash.fromUniversalHashCode
     Hash.by(a => (a.key, a.value))
   }
diff --git a/core/common/src/main/scala/org/typelevel/otel4s/AttributeKey.scala b/core/common/src/main/scala/org/typelevel/otel4s/AttributeKey.scala
index 844031f41..aae0427eb 100644
--- a/core/common/src/main/scala/org/typelevel/otel4s/AttributeKey.scala
+++ b/core/common/src/main/scala/org/typelevel/otel4s/AttributeKey.scala
@@ -80,7 +80,7 @@ object AttributeKey {
   implicit def attributeKeyShow[A]: Show[AttributeKey[A]] =
     Show.show(key => show"${key.`type`}(${key.name})")
 
-  implicit val attributeKeyAnyHash: Hash[AttributeKey[_]] =
+  implicit val attributeKeyExistentialHash: Hash[AttributeKey[_]] =
     Hash.by(key => (key.name, key.`type`))
 
 }
diff --git a/core/common/src/main/scala/org/typelevel/otel4s/AttributeType.scala b/core/common/src/main/scala/org/typelevel/otel4s/AttributeType.scala
index 989b3eeac..aa1c12900 100644
--- a/core/common/src/main/scala/org/typelevel/otel4s/AttributeType.scala
+++ b/core/common/src/main/scala/org/typelevel/otel4s/AttributeType.scala
@@ -41,7 +41,7 @@ object AttributeType {
   implicit def attributeTypeShow[A]: Show[AttributeType[A]] =
     Show.fromToString
 
-  implicit val attributeTypeAnyHash: Hash[AttributeType[_]] =
+  implicit val attributeTypeExistentialHash: Hash[AttributeType[_]] =
     Hash.fromUniversalHashCode
 
 }
diff --git a/core/trace/src/test/scala/org/typelevel/otel4s/trace/SpanKindSuite.scala b/core/trace/src/test/scala/org/typelevel/otel4s/trace/SpanKindSuite.scala
index 1dc03bcd8..e90c0ddf9 100644
--- a/core/trace/src/test/scala/org/typelevel/otel4s/trace/SpanKindSuite.scala
+++ b/core/trace/src/test/scala/org/typelevel/otel4s/trace/SpanKindSuite.scala
@@ -16,13 +16,15 @@
 
 package org.typelevel.otel4s.trace
 
-import cats.Hash
 import cats.Show
+import cats.kernel.laws.discipline.HashTests
 import munit._
+import org.scalacheck.Arbitrary
+import org.scalacheck.Cogen
 import org.scalacheck.Gen
 import org.scalacheck.Prop
 
-class SpanKindSuite extends ScalaCheckSuite {
+class SpanKindSuite extends DisciplineSuite {
 
   private val spanKindGen: Gen[SpanKind] =
     Gen.oneOf(
@@ -33,6 +35,14 @@ class SpanKindSuite extends ScalaCheckSuite {
       SpanKind.Consumer
     )
 
+  private implicit val spanKindArbitrary: Arbitrary[SpanKind] =
+    Arbitrary(spanKindGen)
+
+  private implicit val spanKindCogen: Cogen[SpanKind] =
+    Cogen[String].contramap(_.toString)
+
+  checkAll("SpanKind.HashLaws", HashTests[SpanKind].hash)
+
   property("Show[SpanKind]") {
     Prop.forAll(spanKindGen) { spanKind =>
       val expected = spanKind match {
@@ -47,20 +57,4 @@ class SpanKindSuite extends ScalaCheckSuite {
     }
   }
 
-  test("Hash[SpanKind]") {
-    val allWithIndex = List(
-      SpanKind.Internal,
-      SpanKind.Server,
-      SpanKind.Client,
-      SpanKind.Producer,
-      SpanKind.Consumer
-    ).zipWithIndex
-
-    allWithIndex.foreach { case (that, thatIdx) =>
-      allWithIndex.foreach { case (other, otherIdx) =>
-        assertEquals(Hash[SpanKind].eqv(that, other), thatIdx == otherIdx)
-      }
-    }
-  }
-
 }
diff --git a/core/trace/src/test/scala/org/typelevel/otel4s/trace/StatusSuite.scala b/core/trace/src/test/scala/org/typelevel/otel4s/trace/StatusSuite.scala
index a97bfd249..b55f801fc 100644
--- a/core/trace/src/test/scala/org/typelevel/otel4s/trace/StatusSuite.scala
+++ b/core/trace/src/test/scala/org/typelevel/otel4s/trace/StatusSuite.scala
@@ -16,17 +16,27 @@
 
 package org.typelevel.otel4s.trace
 
-import cats.Hash
 import cats.Show
+import cats.kernel.laws.discipline.HashTests
 import munit._
+import org.scalacheck.Arbitrary
+import org.scalacheck.Cogen
 import org.scalacheck.Gen
 import org.scalacheck.Prop
 
-class StatusSuite extends ScalaCheckSuite {
+class StatusSuite extends DisciplineSuite {
 
   private val statusGen: Gen[Status] =
     Gen.oneOf(Status.Unset, Status.Ok, Status.Error)
 
+  private implicit val statusArbitrary: Arbitrary[Status] =
+    Arbitrary(statusGen)
+
+  private implicit val statusCogen: Cogen[Status] =
+    Cogen[String].contramap(_.toString)
+
+  checkAll("Status.HashLaws", HashTests[Status].hash)
+
   property("Show[Status]") {
     Prop.forAll(statusGen) { status =>
       val expected = status match {
@@ -39,14 +49,4 @@ class StatusSuite extends ScalaCheckSuite {
     }
   }
 
-  test("Hash[Status]") {
-    val allWithIndex = List(Status.Unset, Status.Ok, Status.Error).zipWithIndex
-
-    allWithIndex.foreach { case (that, thatIdx) =>
-      allWithIndex.foreach { case (other, otherIdx) =>
-        assertEquals(Hash[Status].eqv(that, other), thatIdx == otherIdx)
-      }
-    }
-  }
-
 }
diff --git a/core/trace/src/test/scala/org/typelevel/otel4s/trace/TraceFlagsSuite.scala b/core/trace/src/test/scala/org/typelevel/otel4s/trace/TraceFlagsSuite.scala
index 4553952ce..8eba8f882 100644
--- a/core/trace/src/test/scala/org/typelevel/otel4s/trace/TraceFlagsSuite.scala
+++ b/core/trace/src/test/scala/org/typelevel/otel4s/trace/TraceFlagsSuite.scala
@@ -16,9 +16,26 @@
 
 package org.typelevel.otel4s.trace
 
+import cats.Show
+import cats.kernel.laws.discipline.HashTests
 import munit._
+import org.scalacheck.Arbitrary
+import org.scalacheck.Cogen
+import org.scalacheck.Gen
+import org.scalacheck.Prop
 
-class TraceFlagsSuite extends FunSuite {
+class TraceFlagsSuite extends DisciplineSuite {
+
+  private val traceFlagsGen: Gen[TraceFlags] =
+    Gen.chooseNum(0, 255).map(byte => TraceFlags.fromByte(byte.toByte))
+
+  private implicit val traceFlagsArbitrary: Arbitrary[TraceFlags] =
+    Arbitrary(traceFlagsGen)
+
+  private implicit val traceFlagsCogen: Cogen[TraceFlags] =
+    Cogen[Byte].contramap(_.toByte)
+
+  checkAll("TraceFlags.HashLaws", HashTests[TraceFlags].hash)
 
   test("default instances") {
     assertEquals(TraceFlags.Default.toHex, "00")
@@ -51,4 +68,10 @@ class TraceFlagsSuite extends FunSuite {
     assertEquals(TraceFlags.fromHex("zxc"), None)
   }
 
+  property("Show[TraceFlags]") {
+    Prop.forAll(traceFlagsGen) { traceFlags =>
+      assertEquals(Show[TraceFlags].show(traceFlags), traceFlags.toHex)
+    }
+  }
+
 }
diff --git a/sdk/common/src/test/scala/org/typelevel/otel4s/sdk/ArbitraryInstances.scala b/sdk/common/src/test/scala/org/typelevel/otel4s/sdk/ArbitraryInstances.scala
index 30c5a6adf..4da745a87 100644
--- a/sdk/common/src/test/scala/org/typelevel/otel4s/sdk/ArbitraryInstances.scala
+++ b/sdk/common/src/test/scala/org/typelevel/otel4s/sdk/ArbitraryInstances.scala
@@ -17,10 +17,14 @@
 package org.typelevel.otel4s.sdk
 
 import org.scalacheck.Arbitrary
+import org.scalacheck.Cogen
 import org.scalacheck.Gen
 import org.scalacheck.Gen.listOf
 import org.scalacheck.Gen.nonEmptyListOf
+import org.scalacheck.rng.Seed
 import org.typelevel.otel4s.Attribute
+import org.typelevel.otel4s.AttributeKey
+import org.typelevel.otel4s.AttributeType
 
 object arbitrary extends ArbitraryInstances
 trait ArbitraryInstances {
@@ -90,4 +94,40 @@ trait ArbitraryInstances {
     schemaUrl <- Gen.option(nonEmptyString)
   } yield Resource(attrs, schemaUrl))
 
+  implicit val attributeTypeCogen: Cogen[AttributeType[_]] =
+    Cogen[String].contramap(_.toString)
+
+  implicit def attributeKeyCogen[A]: Cogen[AttributeKey[A]] =
+    Cogen[(String, String)].contramap[AttributeKey[A]] { attribute =>
+      (attribute.name, attribute.`type`.toString)
+    }
+
+  implicit def attributeCogen[A: Cogen]: Cogen[Attribute[A]] =
+    Cogen[(AttributeKey[A], A)].contramap(a => (a.key, a.value))
+
+  implicit val attributeExistentialCogen: Cogen[Attribute[_]] =
+    Cogen { (seed, attr) =>
+      def primitive[A: Cogen](seed: Seed): Seed =
+        Cogen[A].perturb(seed, attr.value.asInstanceOf[A])
+
+      def list[A: Cogen](seed: Seed): Seed =
+        Cogen[List[A]].perturb(seed, attr.value.asInstanceOf[List[A]])
+
+      val valueCogen: Seed => Seed = attr.key.`type` match {
+        case AttributeType.Boolean     => primitive[Boolean]
+        case AttributeType.Double      => primitive[Double]
+        case AttributeType.String      => primitive[String]
+        case AttributeType.Long        => primitive[Long]
+        case AttributeType.BooleanList => list[Boolean]
+        case AttributeType.DoubleList  => list[Double]
+        case AttributeType.StringList  => list[String]
+        case AttributeType.LongList    => list[Long]
+      }
+
+      valueCogen(attributeKeyCogen.perturb(seed, attr.key))
+    }
+
+  implicit val attributesCogen: Cogen[Attributes] =
+    Cogen[List[Attribute[_]]].contramap(_.toList)
+
 }
diff --git a/sdk/common/src/test/scala/org/typelevel/otel4s/sdk/AttributesLawTests.scala b/sdk/common/src/test/scala/org/typelevel/otel4s/sdk/AttributesLawTests.scala
index 7e2567e04..dacd414dc 100644
--- a/sdk/common/src/test/scala/org/typelevel/otel4s/sdk/AttributesLawTests.scala
+++ b/sdk/common/src/test/scala/org/typelevel/otel4s/sdk/AttributesLawTests.scala
@@ -16,21 +16,14 @@
 
 package org.typelevel.otel4s.sdk
 
-import cats.Hash
-import cats.implicits.catsKernelStdHashForList
-import cats.kernel.Eq
+import cats.kernel.laws.discipline.HashTests
 import cats.kernel.laws.discipline.MonoidTests
 import munit.DisciplineSuite
-import org.typelevel.otel4s.Attribute
-import org.typelevel.otel4s.sdk.arbitrary.attributes
+import org.typelevel.otel4s.sdk.arbitrary._
 
 class AttributesLawTests extends DisciplineSuite {
 
-  implicit def hashAttribute: Hash[Attribute[_]] =
-    Hash.fromUniversalHashCode[Attribute[_]]
-
-  implicit val attributesEq: Eq[Attributes] = Eq.by(_.toList)
-
+  checkAll("Attributes.HashLaws", HashTests[Attributes].hash)
   checkAll("Attributes.MonoidLaws", MonoidTests[Attributes].monoid)
 
 }
diff --git a/sdk/trace/src/test/scala/org/typelevel/otel4s/sdk/trace/samplers/SamplingDecisionSuite.scala b/sdk/trace/src/test/scala/org/typelevel/otel4s/sdk/trace/samplers/SamplingDecisionSuite.scala
index 8f8ba3b5c..7976e4ce7 100644
--- a/sdk/trace/src/test/scala/org/typelevel/otel4s/sdk/trace/samplers/SamplingDecisionSuite.scala
+++ b/sdk/trace/src/test/scala/org/typelevel/otel4s/sdk/trace/samplers/SamplingDecisionSuite.scala
@@ -16,13 +16,15 @@
 
 package org.typelevel.otel4s.sdk.trace.samplers
 
-import cats.Hash
 import cats.Show
+import cats.kernel.laws.discipline.HashTests
 import munit._
+import org.scalacheck.Arbitrary
+import org.scalacheck.Cogen
 import org.scalacheck.Gen
 import org.scalacheck.Prop
 
-class SamplingDecisionSuite extends ScalaCheckSuite {
+class SamplingDecisionSuite extends DisciplineSuite {
 
   private val samplingDecisionGen: Gen[SamplingDecision] =
     Gen.oneOf(
@@ -31,6 +33,14 @@ class SamplingDecisionSuite extends ScalaCheckSuite {
       SamplingDecision.RecordAndSample
     )
 
+  private implicit val samplingDecisionArbitrary: Arbitrary[SamplingDecision] =
+    Arbitrary(samplingDecisionGen)
+
+  private implicit val samplingDecisionCogen: Cogen[SamplingDecision] =
+    Cogen[String].contramap(_.toString)
+
+  checkAll("SamplingDecision.HashLaws", HashTests[SamplingDecision].hash)
+
   property("is sampled") {
     Prop.forAll(samplingDecisionGen) { decision =>
       val expected = decision match {
@@ -55,21 +65,4 @@ class SamplingDecisionSuite extends ScalaCheckSuite {
     }
   }
 
-  test("Hash[SamplingDecision]") {
-    val allWithIndex = List(
-      SamplingDecision.Drop,
-      SamplingDecision.RecordOnly,
-      SamplingDecision.RecordAndSample
-    ).zipWithIndex
-
-    allWithIndex.foreach { case (that, thatIdx) =>
-      allWithIndex.foreach { case (other, otherIdx) =>
-        assertEquals(
-          Hash[SamplingDecision].eqv(that, other),
-          thatIdx == otherIdx
-        )
-      }
-    }
-  }
-
 }

From 571900a62b0d55c7ad529a14b43325fe7437341f Mon Sep 17 00:00:00 2001
From: Maksym Ochenashko <maxochenashko@gmail.com>
Date: Wed, 4 Oct 2023 10:32:07 +0300
Subject: [PATCH 3/4] Add more tests

---
 .../org/typelevel/otel4s/sdk/Resource.scala   |  2 +-
 .../otel4s/sdk/ArbitraryInstances.scala       |  5 ++++
 .../otel4s/sdk/AttributesProps.scala          | 14 +++++++++-
 .../otel4s/sdk/ResourceLawTests.scala         | 27 +++++++++++++++++++
 .../typelevel/otel4s/sdk/ResourceProps.scala  | 11 ++++++++
 .../typelevel/otel4s/sdk/ResourceSuite.scala  | 12 +++++++--
 6 files changed, 67 insertions(+), 4 deletions(-)
 create mode 100644 sdk/common/src/test/scala/org/typelevel/otel4s/sdk/ResourceLawTests.scala

diff --git a/sdk/common/src/main/scala/org/typelevel/otel4s/sdk/Resource.scala b/sdk/common/src/main/scala/org/typelevel/otel4s/sdk/Resource.scala
index d4d071bf5..069f01e90 100644
--- a/sdk/common/src/main/scala/org/typelevel/otel4s/sdk/Resource.scala
+++ b/sdk/common/src/main/scala/org/typelevel/otel4s/sdk/Resource.scala
@@ -62,7 +62,7 @@ final case class Resource(
 
       schemaUrlOptEither.map(
         Resource(
-          other.attributes |+| attributes,
+          attributes |+| other.attributes,
           _
         )
       )
diff --git a/sdk/common/src/test/scala/org/typelevel/otel4s/sdk/ArbitraryInstances.scala b/sdk/common/src/test/scala/org/typelevel/otel4s/sdk/ArbitraryInstances.scala
index 4da745a87..335f8079a 100644
--- a/sdk/common/src/test/scala/org/typelevel/otel4s/sdk/ArbitraryInstances.scala
+++ b/sdk/common/src/test/scala/org/typelevel/otel4s/sdk/ArbitraryInstances.scala
@@ -130,4 +130,9 @@ trait ArbitraryInstances {
   implicit val attributesCogen: Cogen[Attributes] =
     Cogen[List[Attribute[_]]].contramap(_.toList)
 
+  implicit val resourceCogen: Cogen[Resource] =
+    Cogen[(Attributes, Option[String])].contramap { r =>
+      (r.attributes, r.schemaUrl)
+    }
+
 }
diff --git a/sdk/common/src/test/scala/org/typelevel/otel4s/sdk/AttributesProps.scala b/sdk/common/src/test/scala/org/typelevel/otel4s/sdk/AttributesProps.scala
index c04804092..e189b504b 100644
--- a/sdk/common/src/test/scala/org/typelevel/otel4s/sdk/AttributesProps.scala
+++ b/sdk/common/src/test/scala/org/typelevel/otel4s/sdk/AttributesProps.scala
@@ -17,13 +17,15 @@
 package org.typelevel.otel4s.sdk
 
 import cats.Id
-import cats.implicits.catsSyntaxSemigroup
+import cats.Show
+import cats.syntax.semigroup._
 import munit.ScalaCheckSuite
 import org.scalacheck.Arbitrary
 import org.scalacheck.Gen
 import org.scalacheck.Prop.forAll
 import org.typelevel.otel4s.Attribute
 import org.typelevel.otel4s.sdk.arbitrary.attribute
+import org.typelevel.otel4s.sdk.arbitrary.attributes
 
 class AttributesProps extends ScalaCheckSuite {
 
@@ -128,4 +130,14 @@ class AttributesProps extends ScalaCheckSuite {
     }
   }
 
+  property("Show[Attributes]") {
+    forAll(attributes.arbitrary) { attributes =>
+      val expected = attributes.toList
+        .map(Show[Attribute[_]].show)
+        .mkString("Attributes(", ", ", ")")
+
+      assertEquals(Show[Attributes].show(attributes), expected)
+    }
+  }
+
 }
diff --git a/sdk/common/src/test/scala/org/typelevel/otel4s/sdk/ResourceLawTests.scala b/sdk/common/src/test/scala/org/typelevel/otel4s/sdk/ResourceLawTests.scala
new file mode 100644
index 000000000..4f28648ee
--- /dev/null
+++ b/sdk/common/src/test/scala/org/typelevel/otel4s/sdk/ResourceLawTests.scala
@@ -0,0 +1,27 @@
+/*
+ * Copyright 2023 Typelevel
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.typelevel.otel4s.sdk
+
+import cats.kernel.laws.discipline.HashTests
+import munit.DisciplineSuite
+import org.typelevel.otel4s.sdk.arbitrary._
+
+class ResourceLawTests extends DisciplineSuite {
+
+  checkAll("Resource.HashLaws", HashTests[Resource].hash)
+
+}
diff --git a/sdk/common/src/test/scala/org/typelevel/otel4s/sdk/ResourceProps.scala b/sdk/common/src/test/scala/org/typelevel/otel4s/sdk/ResourceProps.scala
index cb4af061e..488016cb4 100644
--- a/sdk/common/src/test/scala/org/typelevel/otel4s/sdk/ResourceProps.scala
+++ b/sdk/common/src/test/scala/org/typelevel/otel4s/sdk/ResourceProps.scala
@@ -17,6 +17,8 @@
 package org.typelevel.otel4s.sdk
 
 import cats.Id
+import cats.Show
+import cats.syntax.show._
 import munit.ScalaCheckSuite
 import org.scalacheck.Prop.forAll
 import org.typelevel.otel4s.sdk.arbitrary.resource
@@ -44,4 +46,13 @@ class ResourceProps extends ScalaCheckSuite {
     }
   }
 
+  property("Show[Resource]") {
+    forAll(resource.arbitrary) { resource =>
+      val expected =
+        show"Resource{attributes=${resource.attributes}, schemaUrl=${resource.schemaUrl}}"
+
+      assertEquals(Show[Resource].show(resource), expected)
+    }
+  }
+
 }
diff --git a/sdk/common/src/test/scala/org/typelevel/otel4s/sdk/ResourceSuite.scala b/sdk/common/src/test/scala/org/typelevel/otel4s/sdk/ResourceSuite.scala
index 50ed945b8..de75cd99b 100644
--- a/sdk/common/src/test/scala/org/typelevel/otel4s/sdk/ResourceSuite.scala
+++ b/sdk/common/src/test/scala/org/typelevel/otel4s/sdk/ResourceSuite.scala
@@ -14,9 +14,10 @@
  * limitations under the License.
  */
 
-package org.typelevel.otel4s.sdk
+package org.typelevel.otel4s
+package sdk
 
-import cats.implicits.catsSyntaxEitherId
+import cats.syntax.either._
 import munit.FunSuite
 import org.typelevel.otel4s.sdk.Resource.ResourceInitiationError
 import org.typelevel.otel4s.sdk.Resource.ResourceInitiationError.SchemaUrlConflict
@@ -81,4 +82,11 @@ class ResourceSuite extends FunSuite {
     checkSchemaMerge(None, None, None.asRight)
   }
 
+  test("Resource#mergeInto - merge attributes and prioritize the latter") {
+    val that = Resource(Attributes(Attribute("key", "that")))
+    val other = Resource(Attributes(Attribute("key", "other")))
+
+    assertEquals(that.mergeInto(other), Right(other))
+  }
+
 }

From 8e79f83e561eeb190e53a221e15c76eb6f8a5d3a Mon Sep 17 00:00:00 2001
From: Maksym Ochenashko <maxochenashko@gmail.com>
Date: Fri, 6 Oct 2023 10:05:46 +0300
Subject: [PATCH 4/4] Use `import cats.syntax.all._`

---
 .../src/main/scala/org/typelevel/otel4s/sdk/Resource.scala   | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/sdk/common/src/main/scala/org/typelevel/otel4s/sdk/Resource.scala b/sdk/common/src/main/scala/org/typelevel/otel4s/sdk/Resource.scala
index 069f01e90..3547b19ed 100644
--- a/sdk/common/src/main/scala/org/typelevel/otel4s/sdk/Resource.scala
+++ b/sdk/common/src/main/scala/org/typelevel/otel4s/sdk/Resource.scala
@@ -18,10 +18,7 @@ package org.typelevel.otel4s.sdk
 
 import cats.Hash
 import cats.Show
-import cats.syntax.either._
-import cats.syntax.option._
-import cats.syntax.semigroup._
-import cats.syntax.show._
+import cats.syntax.all._
 import org.typelevel.otel4s.Attribute
 import org.typelevel.otel4s.sdk.Resource.ResourceInitiationError
 import org.typelevel.otel4s.semconv.resource.attributes.ResourceAttributes._