Where are the ChaCha20 test vectors/examples?
There are in the RFC : http://tools.ietf.org/html/draft-agl-tls-chacha20poly1305-04#section-7


  The following blocks contain test vectors for ChaCha20.  The first    line contains the 256-bit key, the second the 64-bit nonce and the
  last line contains a prefix of the resulting ChaCha20 key-stream.
  
  KEY:       00000000000000000000000000000000000000000000000000000000
                00000000
  NONCE:     0000000000000000
  KEYSTREAM: 76b8e0ada0f13d90405d6ae55386bd28bdd219b8a08ded1aa836efcc
                8b770dc7da41597c5157488d7724e03fb8d84a376a43b8f41518a11c
                c387b669b2ee6586
  
  KEY:       00000000000000000000000000000000000000000000000000000000
                00000001
  NONCE:     0000000000000000
  KEYSTREAM: 4540f05a9f1fb296d7736e7b208e3c96eb4fe1834688d2604f450952
                ed432d41bbe2a0b6ea7566d2a5d1e7e20d42af2c53d792b1c43fea81
                7e9ad275ae546963
  
  KEY:       00000000000000000000000000000000000000000000000000000000
                00000000
  NONCE:     0000000000000001
  KEYSTREAM: de9cba7bf3d69ef5e786dc63973f653a0b49e015adbff7134fcb7df1
                37821031e85a050278a7084527214f73efc7fa5b5277062eb7a0433e
                445f41e3
  
  KEY:       00000000000000000000000000000000000000000000000000000000
                00000000
  NONCE:     0100000000000000
  KEYSTREAM: ef3fdfd6c61578fbf5cf35bd3dd33b8009631634d21e42ac33960bd1
                38e50d32111e4caf237ee53ca8ad6426194a88545ddc497a0b466e7d
                6bbdb0041b2f586b