Add test for multi-dir merging

test/merge_multiple_dirs.sh

@@ -0,0 +1,77 @@
+#!/bin/sh
+
+TRY_TOP="${TRY_TOP:-$(git rev-parse --show-toplevel --show-superproject-working-tree)}"
+TRY="$TRY_TOP/try"
+
+cleanup() {
+    cd /
+
+    if [ -d "$try_workspace" ]
+    then
+        rm -rf "$try_workspace" >/dev/null 2>&1
+    fi
+
+    if [ -f "$try_example_dir1" ]
+    then
+        rm "$try_example_dir1"
+    fi
+
+    if [ -f "$try_example_dir2" ]
+    then
+        rm "$try_example_dir2"
+    fi
+
+    if [ -f "$try_example_dir3" ]
+    then
+        rm "$try_example_dir3"
+    fi
+
+    if [ -f "$expected1" ]
+    then
+       rm "$expected1"
+    fi
+
+    if [ -f "$expected2" ]
+    then
+       rm "$expected2"
+    fi
+
+    if [ -f "$expected3" ]
+    then
+       rm "$expected3"
+    fi
+
+    if [ -f "$expected4" ]
+    then
+       rm "$expected4"
+    fi
+}
+
+trap 'cleanup' EXIT
+
+try_workspace="$(mktemp -d -p .)"
+cp "$TRY_TOP/test/resources/file.txt.gz" "$try_workspace/"
+cd $try_workspace
+
+try_example_dir1="$(mktemp -d)"
+try_example_dir2="$(mktemp -d)"
+try_example_dir3="$(mktemp -d)"
+
+expected1="$(mktemp)"
+expected2="$(mktemp)"
+expected3="$(mktemp)"
+
+touch "$expected1"
+echo "test2" > $expected2
+echo "test3" > $expected3
+
+"$TRY" -D "$try_example_dir1" "touch file_1.txt; echo test > file_2.txt; rm file.txt.gz" || return 1
+"$TRY" -D "$try_example_dir2" "echo test2 > file_2.txt" || return 2
+"$TRY" -D "$try_example_dir3" "echo test3 > file_3.txt" || return 3
+"$TRY" -L "$try_example_dir3:$try_example_dir2:$try_example_dir1" -y "cat file_1.txt > out1; cat file_2.txt > out2; cat file_3.txt > out3"|| return 4
+
+diff -q "$expected1" out1 || return 5
+diff -q "$expected2" out2 || return 6
+diff -q "$expected3" out3 || return 7
+
+! [ -f out4 ] || return 8