test: add test samples

Adds test samples that can be used for unit tests or to verify
implementations via:
```bash
for sample in $(ls src/test/resources/samples/*.txt)
do
  echo "Validating $sample"
  rm -f measurements.txt
  ln -s $sample measurements.txt

  diff <(./calculate_average.sh) ${sample%.txt}.out
done
rm measurements.txt
```

For #61

1 files changed, 1 insertions, 0 deletions

diff --git a/src/test/resources/samples/measurements-1.out b/src/test/resources/samples/measurements-1.out
new file mode 100644
index 0000000..27a2a6e
--- /dev/null
+++ b/src/test/resources/samples/measurements-1.out
@@ -0,0 +1 @@
+{Kunming=19.8/19.8/19.8}