Add test harness for various library loading methods

test/fixtures/bats/load.bats

@@ -1,6 +1,27 @@
 [ -n "$HELPER_NAME" ] || HELPER_NAME="test_helper"
 load "$HELPER_NAME"
 
+BATS_LIB_PATH="$BATS_TEST_DIRNAME/load_path" \
+    load "${HELPER_LIB_SINGLE_FILE:-single_file}"
+
+BATS_LIB_PATH="$BATS_TEST_DIRNAME/load_path" \
+    load "${HELPER_LIB_NO_LOADER:-no_loader}"
+
+BATS_LIB_PATH="$BATS_TEST_DIRNAME/load_path" \
+    load "${HELPER_LIB_WITH_LOADER:-with_loader}"
+
 @test "calling a loaded helper" {
   help_me
 }
+
+@test "calling a library helper" {
+    lib_func
+}
+
+@test "calling a helper from library without loading file" {
+    no_loader
+}
+
+@test "calling a helper from library with loading file" {
+    with_loader
+}

test/fixtures/bats/load_path/no_loader/no_loader.bash

@@ -0,0 +1,3 @@
+no_loader() {
+    true
+}

test/fixtures/bats/load_path/single_file.bash

@@ -0,0 +1,3 @@
+lib_func() {
+    true
+}

test/fixtures/bats/load_path/with_loader.bash

@@ -0,0 +1 @@
+source "$(dirname ${BASH_SOURCE[0]})/with_loader/a-file.bash"

test/fixtures/bats/load_path/with_loader/a-file.bash

@@ -0,0 +1,3 @@
+with_loader() {
+    true
+}