1 files changed, 56 insertions, 0 deletions
diff --git a/tests/unit/test_btrfs.bats b/tests/unit/test_btrfs.bats
new file mode 100644
index 0000000..890bba2
--- /dev/null
+++ b/tests/unit/test_btrfs.bats
@@ -0,0 +1,56 @@
+#!/usr/bin/env bats
+# Unit tests for installer/lib/btrfs.sh
+#
+# Coverage scope: pure helpers only. Most of btrfs.sh wraps cryptsetup,
+# mkfs.btrfs, snapper, grub-install, and arch-chroot — all deliberately
+# VM-tested per the project's testing-strategy.org policy. Only
+# get_luks_devices is covered here.
+
+setup() {
+    # shellcheck disable=SC1091
+    source "${BATS_TEST_DIRNAME}/../../installer/lib/common.sh"
+    # shellcheck disable=SC1091
+    source "${BATS_TEST_DIRNAME}/../../installer/lib/btrfs.sh"
+}
+
+#############################
+# get_luks_devices
+#############################
+# Asymmetric naming: index 0 uses the bare LUKS_MAPPER_NAME (no
+# suffix), subsequent indices append the index. Tests pin both the
+# bare-first behavior and the suffix-on-rest behavior.
+
+@test "get_luks_devices: count=1 emits the bare-named mapper device" {
+    LUKS_MAPPER_NAME="cryptroot"
+    run get_luks_devices 1
+    [ "$status" -eq 0 ]
+    [ "$output" = "/dev/mapper/cryptroot" ]
+}
+
+@test "get_luks_devices: count=3 emits bare name + suffixed entries" {
+    LUKS_MAPPER_NAME="cryptroot"
+    run get_luks_devices 3
+    [ "$status" -eq 0 ]
+    [ "$output" = "/dev/mapper/cryptroot /dev/mapper/cryptroot1 /dev/mapper/cryptroot2" ]
+}
+
+@test "get_luks_devices: count=0 emits empty output" {
+    LUKS_MAPPER_NAME="cryptroot"
+    run get_luks_devices 0
+    [ "$status" -eq 0 ]
+    [ -z "$output" ]
+}
+
+@test "get_luks_devices: count=5 emits five entries with correct suffix progression" {
+    LUKS_MAPPER_NAME="cryptroot"
+    run get_luks_devices 5
+    [ "$status" -eq 0 ]
+    [ "$output" = "/dev/mapper/cryptroot /dev/mapper/cryptroot1 /dev/mapper/cryptroot2 /dev/mapper/cryptroot3 /dev/mapper/cryptroot4" ]
+}
+
+@test "get_luks_devices: non-numeric count is treated as zero (no crash)" {
+    LUKS_MAPPER_NAME="cryptroot"
+    run get_luks_devices abc
+    [ "$status" -eq 0 ]
+    [ -z "$output" ]
+}