diff --git a/.travis.yml b/.travis.yml
index 64e1c52..60d8fd7 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -5,3 +5,4 @@ os:
 
 script:
     - shellcheck -s bash --exclude=SC2034,SC2154 <(awk '/```sh/{f=1;next}/```/{f=0}f' README.md)
+    - ./test.sh
diff --git a/README.md b/README.md
index fb0c73a..c8ccc04 100644
--- a/README.md
+++ b/README.md
@@ -102,8 +102,8 @@ scripts and not full blown utilities.
 ### Trim leading and trailing white-space from string.
 
 ```sh
-trim() {
-    # Usage: trim "   example   string    "
+trim_string() {
+    # Usage: trim_string "   example   string    "
     : "${1#"${1%%[![:space:]]*}"}"
     : "${_%"${_##*[![:space:]]}"}"
     printf '%s\n' "$_"
@@ -114,7 +114,7 @@ trim() {
 
 ```sh
 # shellcheck disable=SC2086,SC2048
-trim() {
+trim_all() {
     # Usage: trim "   example   string    "
     set -f
     set -- $*
@@ -226,10 +226,8 @@ reverse_array() {
     # Usage: reverse_array "array"
     #        reverse_array 1 2 3 4 5 6
     shopt -s extdebug
-    f()(printf '%s ' "${BASH_ARGV[@]}"); f "$@"
+    f()(printf '%s\n' "${BASH_ARGV[@]}"); f "$@"
     shopt -u extdebug
-
-    printf '\n'
 }
 ```
 
@@ -547,7 +545,7 @@ _() {
 
     # Undocumented method.
     # Note: This is commented to make shellcheck play nice.
-    for i in {1..10};{ echo "$i";}
+    # for i in {1..10};{ echo "$i";}
 
     # Expansion.
     for i in {1..10}; do echo "$i"; done
@@ -586,9 +584,10 @@ _() {
     f()(($1))
 
     # Using tests, loops etc.
-    # Note: You can also use ‘while’, ‘until’, ‘case’, ‘(())’, ‘[[]]’.
-    f()if true; then echo "$1"; fi
-    f()for i in "$@"; do echo "$i"; done
+    # NOTE: You can also use ‘while’, ‘until’, ‘case’, ‘(())’, ‘[[]]’.
+    # NOTE: These are commented to make shellcheck play nice.
+    # f()if true; then echo "$1"; fi
+    # f()for i in "$@"; do echo "$i"; done
 }
 ```
 
diff --git a/test.sh b/test.sh
new file mode 100755
index 0000000..32a301f
--- /dev/null
+++ b/test.sh
@@ -0,0 +1,149 @@
+#!/usr/bin/env bash
+#
+# Tests for the Pure Bash Bible.
+
+test_trim_string() {
+    result="$(trim_string "    Hello,    World    ")"
+    assert_equals "$result" "Hello,    World"
+}
+
+test_trim_all() {
+    result="$(trim_all "    Hello,    World    ")"
+    assert_equals "$result" "Hello, World"
+}
+
+test_lower() {
+    result="$(lower "HeLlO")"
+    assert_equals "$result" "hello"
+}
+
+test_upper() {
+    result="$(upper "HeLlO")"
+    assert_equals "$result" "HELLO"
+}
+
+test_trim_quotes() {
+    result="$(trim_quotes "\"te'st' 'str'ing\"")"
+    assert_equals "$result" "test string"
+}
+
+test_lstrip() {
+    result="$(lstrip "!:IHello" "!:I")"
+    assert_equals "$result" "Hello"
+}
+
+test_rstrip() {
+    result="$(rstrip "Hello!:I" "!:I")"
+    assert_equals "$result" "Hello"
+}
+
+test_reverse_array() {
+    IFS=$'\n' read -d "" -ra result < <(reverse_array 1 2 3 4 5)
+    assert_equals "${result[*]}" "5 4 3 2 1"
+}
+
+test_remove_array_dups() {
+    IFS=$'\n' read -d "" -ra result < <(remove_array_dups 1 1 2 2 3 3 4 5)
+    assert_equals "${result[*]}" "1 2 3 4 5"
+}
+
+test_cycle() {
+    # shellcheck disable=2034
+    arr=(a b c d)
+    result="$(cycle; cycle; cycle)"
+    assert_equals "$result" "a b c "
+}
+
+test_head() {
+    printf '%s\n%s\n\n\n' "hello" "world" > test_file
+    result="$(head 2 test_file)"
+    assert_equals "$result" $'hello\nworld'
+    rm test_file
+}
+
+test_tail() {
+    printf '\n\n\n%s\n%s\n' "hello" "world" > test_file
+    result="$(tail 2 test_file)"
+    assert_equals "$result" $'hello\nworld'
+    rm test_file
+}
+
+test_count() {
+    result="$(count ./{README.m,LICENSE.m,.travis.ym}*)"
+    assert_equals "$result" "3"
+}
+
+test_dirname() {
+    result="$(dirname "/home/black/Pictures/Wallpapers/1.jpg")"
+    assert_equals "$result" "/home/black/Pictures/Wallpapers/"
+}
+
+test_basename() {
+    result="$(basename "/home/black/Pictures/Wallpapers/1.jpg")"
+    assert_equals "$result" "1.jpg"
+}
+
+test_hex_to_rgb() {
+    result="$(hex_to_rgb "#FFFFFF")"
+    assert_equals "$result" "255 255 255"
+}
+
+test_rgb_to_hex() {
+    result="$(rgb_to_hex 0 0 0)"
+    assert_equals "$result" "#000000"
+}
+
+test_date() {
+    result="$(date "%C")"
+    assert_equals "$result" "20"
+}
+
+assert_equals() {
+    local status
+    ((tests+=1))
+
+    [[ "$1" == "$2" ]] && status="✔"
+    printf '%s\n' " ${status:-✖} | ${FUNCNAME[1]/test_}"
+
+    if [[ "$1" == "$2" ]]; then
+        ((pass+=1))
+        return 0
+    else
+        :>/tmp/err
+        ((err+=1))
+        return 1
+    fi
+}
+
+main() {
+    source <(awk '/```sh/{f=1;next}/```/{f=0}f' README.md) 2>/dev/null
+
+    head="-> Running tests on the Pure Bash Bible.."
+    printf '\n%s\n%s\n' "$head" "${head//?/-}"
+
+    test_trim_string
+    test_trim_all
+    test_lower
+    test_upper
+    test_trim_quotes
+    test_lstrip
+    test_rstrip
+    test_reverse_array
+    test_remove_array_dups
+    test_cycle
+    test_head
+    test_tail
+    test_count
+    test_dirname
+    test_basename
+    test_hex_to_rgb
+    test_rgb_to_hex
+    test_date
+
+    comp="Completed $tests tests. ${pass:-0} passed, ${err:-0} errored."
+    printf '%s\n%s\n\n' "${comp//?/-}" "$comp"
+
+    [[ -f /tmp/err ]] || exit 0 && { rm /tmp/err; exit 1; }
+}
+
+main "$@"