Added tests

test.sh

@@ -0,0 +1,27 @@
+#!/usr/bin/env bash
+#
+# Tests for the Pure Bash Bible.
+
+assert_equals() {
+    # Test equality.
+    local status
+    [[ "$1" == "$2" ]] && status="✔"
+    printf '%s\n' "  ${status:-✖} : ${FUNCNAME[1]}"
+    [[ "$1" == "$2" ]] || { :>/tmp/err; return 1; } && return 0
+}
+
+test_trim() {
+    result="$(trim "    Hello,    World    ")"
+    assert_equals "$result" "Hello,    World"
+}
+
+main() {
+    source <(awk '/```sh/{f=1;next}/```/{f=0}f' README.md) 2>/dev/null
+
+    test_trim
+
+    [[ -f /tmp/err ]] || exit 0 && { rm /tmp/err; exit 1; }
+}
+
+main "$@"
+