diff --git a/tests/testthat/test-merging.R b/tests/testthat/test-merging.R
new file mode 100644
index 0000000..0f31145
--- /dev/null
+++ b/tests/testthat/test-merging.R
@@ -0,0 +1,104 @@
+# Structural change -------------------------------------------------------
+
+# Example of a structural change (named to unnamed)
+# Expectation:
+# Entire 'host' element should be overwritten
+
+test_that("Merging: structural change (named to unnamed)", {
+  result <- get(
+    file = test_path("merging/config_01.yml"),
+    config = "prod"
+  )
+
+  expectation <- structure(
+    list(
+      host = list(
+        list(id = "server_001", url = "https://prod-server-001.com",
+          port = 8000L),
+        list(id = "server_002", url = "https://prod-server-002.com",
+          port = 8000L)
+      ), hello = list(world = TRUE)),
+    config = "prod",
+    file = "path/to/config/file"
+  )
+
+  expect_equivalent(result, expectation)
+})
+
+# Unnamed list: simple ----------------------------------------------------
+
+# Example of merging unnamed lists where UID information is contained in
+# non-nested list
+# Expectation:
+# - server_001 should be overwritten
+# - server_002 shold be kept
+# - server_003 should be added
+
+test_that("Merging: unnamed: simple", {
+  result <- get(
+    file = test_path("merging/config_02.yml"),
+    config = "peak"
+  )
+
+  expectation <- structure(
+    list(
+      host = list(
+        list(id = "server_001", url = "https://peak-server-001.com",
+          port = 8000L),
+        list(id = "server_002", url = "https://standard-server-002.com",
+          port = 8000L),
+        list(id = "server_003", url = "https://standard-server-003.com",
+          port = 8000L)
+      ),
+      hello = list(world = TRUE)
+    ),
+    config = "peak",
+    file = "path/to/config/file"
+  )
+
+  expect_equivalent(result, expectation)
+})
+
+# Unnamed list: nested ----------------------------------------------------
+
+# Example of merging unnamed lists where UID information is contained in nested
+# list
+# Expectation:
+# - server_001 should be overwritten
+# - server_002 shold be kept
+# - server_003 should be added
+
+test_that("Merging: unnamed: nested", {
+  result <- get(
+    file = test_path("merging/config_03.yml"),
+    config = "peak"
+  )
+
+  expectation <-structure(
+    list(
+      host = list(
+        list(
+          info = list(id = "server-001",
+            description = "peak server-001"),
+          url = "https://peak-server-001.com",
+          port = 8000L
+        ),
+        list(
+          info = list(id = "server-002", description = "standard server-002"),
+          url = "https://standard-server-002.com",
+          port = 8000L
+        ),
+        list(
+          info = list(id = "server-003", description = "standard server-003"),
+          url = "https://standard-server-003.com",
+          port = 8000L
+        )
+      ),
+      hello = list(world = TRUE)
+    ),
+    config = "peak",
+    file = "path/to/config/file"
+  )
+
+  expect_equivalent(result, expectation)
+})