Add tests for pointer extensions

Author: Oleg

src/commonTest/kotlin/smirnov.oleg.json/pointer/JsonPointerExtensionsTest.kt

@@ -0,0 +1,55 @@
+package smirnov.oleg.json.pointer
+
+import io.kotest.core.spec.style.FunSpec
+import io.kotest.matchers.shouldBe
+import smirnov.oleg.json.pointer.JsonPointer.Companion
+
+@Suppress("unused")
+class JsonPointerExtensionsTest : FunSpec() {
+  init {
+    data class TestCase<T>(
+      val firstArg: JsonPointer,
+      val secondArg: T,
+      val result: JsonPointer,
+    )
+
+    listOf(
+      TestCase(JsonPointer.ROOT, "prop", JsonPointer("/prop")),
+      TestCase(JsonPointer("/test"), "prop", JsonPointer("/test/prop")),
+    ).forEach { (initial, prop, result) ->
+      test("$initial / $prop => $result") {
+        (initial / prop) shouldBe result
+      }
+    }
+
+    listOf(
+      TestCase(JsonPointer.ROOT, 0, JsonPointer("/0")),
+      TestCase(JsonPointer("/test"), 0, JsonPointer("/test/0")),
+    ).forEach { (initial, prop, result) ->
+      test("$initial [ $prop ] => $result") {
+        (initial[prop]) shouldBe result
+      }
+    }
+
+    listOf(
+      TestCase(JsonPointer.ROOT, JsonPointer.ROOT, JsonPointer.ROOT),
+      TestCase(JsonPointer.ROOT, JsonPointer("/test"), JsonPointer("/test")),
+      TestCase(JsonPointer("/test"), JsonPointer.ROOT, JsonPointer("/test")),
+      TestCase(JsonPointer("/test1"), JsonPointer("/test2"), JsonPointer("/test1/test2")),
+    ).forEach { (init, append, result) ->
+      test("$init + $append => $result") {
+        (init + append) shouldBe result
+      }
+    }
+
+    listOf(
+      TestCase(JsonPointer.ROOT, JsonPointer.ROOT, JsonPointer.ROOT),
+      TestCase(JsonPointer.ROOT, JsonPointer("/test"), JsonPointer("/test")),
+      TestCase(JsonPointer("/test"), JsonPointer("/test/data"), JsonPointer("/data")),
+    ).forEach { (base, relativeToBase, relativePath) ->
+      test("relative path from '$base' to '$relativeToBase' is '$relativePath'") {
+        base.relative(relativeToBase) shouldBe relativePath
+      }
+    }
+  }
+}