From 4f9b336934b513b7ffbd9db829ea7159ff4c4b3f Mon Sep 17 00:00:00 2001
From: Daniel Slapman <danslapman@gmail.com>
Date: Sun, 5 Jan 2025 14:36:49 +0100
Subject: [PATCH] Fix `:+` operator

---
 .../src/main/scala/oolong/bson/bson.scala     |  2 +-
 .../scala/oolong/bson/BsonMergeSpec.scala     | 25 +++++++++++++++++++
 2 files changed, 26 insertions(+), 1 deletion(-)
 create mode 100644 oolong-bson/src/test/scala/oolong/bson/BsonMergeSpec.scala

diff --git a/oolong-bson/src/main/scala/oolong/bson/bson.scala b/oolong-bson/src/main/scala/oolong/bson/bson.scala
index fc2eabb..11702fb 100644
--- a/oolong-bson/src/main/scala/oolong/bson/bson.scala
+++ b/oolong-bson/src/main/scala/oolong/bson/bson.scala
@@ -76,7 +76,7 @@ extension (bv: BsonValue)
    *
    * In a case of key collision bson1 values takes priority
    */
-  @inline def :+(other: BsonValue): BsonValue = merge(other, bv, false)
+  @inline def :+(other: BsonValue): BsonValue = merge(bv, other, false)
 
   /**
    * Merges two bson values
diff --git a/oolong-bson/src/test/scala/oolong/bson/BsonMergeSpec.scala b/oolong-bson/src/test/scala/oolong/bson/BsonMergeSpec.scala
new file mode 100644
index 0000000..c993270
--- /dev/null
+++ b/oolong-bson/src/test/scala/oolong/bson/BsonMergeSpec.scala
@@ -0,0 +1,25 @@
+package oolong.bson
+
+import org.mongodb.scala.bson.*
+import org.scalatest.funsuite.AnyFunSuite
+import org.scalatest.matchers.should.Matchers
+
+class BsonMergeSpec extends AnyFunSuite with Matchers {
+  test(":+ document merge") {
+    val doc1 = BsonDocument("field1" -> 10, "field2" -> 30)
+    val doc2 = BsonDocument("field1" -> 20, "field3" -> 40)
+
+    val res = doc1 :+ doc2
+
+    res shouldBe BsonDocument("field1" -> 10, "field2" -> 30, "field3" -> 40)
+  }
+
+  test("+: document merge") {
+    val doc1 = BsonDocument("field1" -> 10, "field2" -> 30)
+    val doc2 = BsonDocument("field1" -> 20, "field3" -> 40)
+
+    val res = doc1 +: doc2
+
+    res shouldBe BsonDocument("field1" -> 20, "field2" -> 30, "field3" -> 40)
+  }
+}