Add testing guide and update README with testing section

README.md

@@ -58,6 +58,10 @@ See [`docs/cheatsheet.md`](docs/cheatsheet.md) for a map of Finnish grammatical
 | `examples/async/` | DOM click handlers, mutable state |
 | `examples/program/` | Capstone combining recursion and list iteration |
 
+## Testing
+
+See [`docs/testing.md`](docs/testing.md) for a step-by-step guide to verifying each example.
+
 ## Local Setup (without Docker)
 
 See [`docs/install.md`](docs/install.md) for instructions on installing `libvoikko` and `tampio` natively.

docs/testing.md

@@ -0,0 +1,97 @@
+# Testing the Examples
+
+## Build and serve
+
+```sh
+make
+python3 -m http.server 9994 --directory examples
+```
+
+Open `http://localhost:9994/basics/index.html` for the full index, or test each example directly below.
+
+---
+
+## basics/hello.html
+
+`http://localhost:9994/basics/hello.html`
+
+- Page loads → browser alert says **Hei maailma!**
+
+---
+
+## basics/factorial.html
+
+`http://localhost:9994/basics/factorial.html`
+
+- Page loads → prompt appears
+- Enter `5` → alert shows **120**
+- Enter `0` → alert shows **1**
+
+---
+
+## basics/fibonacci.html
+
+`http://localhost:9994/basics/fibonacci.html`
+
+- Page loads → prompt appears
+- Enter `10` → alert shows **55**
+- Enter `1` → alert shows **1**
+
+---
+
+## data-structures/lista.html
+
+`http://localhost:9994/data-structures/lista.html`
+
+- Right panel shows the list `[3, 1, 4, 1, 5]`
+- Size: **5**, first element: **3**
+- Ascending sort: **1 1 3 4 5**
+- Descending sort: **5 4 3 1 1**
+
+---
+
+## data-structures/vektori.html
+
+`http://localhost:9994/data-structures/vektori.html`
+
+- Dimension: **2**
+- Sum: **7**
+- Length (3-4-5 triangle): **5**
+
+---
+
+## strings/merkkijono.html
+
+`http://localhost:9994/strings/merkkijono.html`
+
+- Merkkijono: **Hei, Tampio!**
+- Pituus: **12**
+- Yhdistetty: **Hei, Tampio! Vuosi 2026.**
+- Siistitty: **'välilyönnit poistuvat'**
+- Hedelmät: **omena banaani kiivi**
+
+---
+
+## async/nappi.html
+
+`http://localhost:9994/async/nappi.html`
+
+- Two buttons visible: **+1** and **+10**
+- Click **+1** → one `▪` dot appears
+- Click **+10** → ten `▪` dots appear
+- Dots accumulate across clicks
+
+---
+
+## program/kasvutaulukko.html
+
+`http://localhost:9994/program/kasvutaulukko.html`
+
+- **Kertoma (n!)** section shows: `1 1 2 6 24 120 720`
+- **Fibonacci-kani (fib(n))** section shows: `1 1 2 3 5 8 13`
+
+---
+
+## Checking for errors
+
+Open browser DevTools (`F12` → Console) on any page and verify no red errors appear. The only expected output is from the examples themselves.