[tree] random ascii strain name testing

This test generates random ASCII names. It's disabled for CI as it's
both stochastic and slow but you can easily toggle it back on (by
uncommenting the function call) if you want to better test strain name
handling in `augur tree`

tests/functional/tree/cram/generate-fasta.py

@@ -0,0 +1,28 @@
+import random
+
+def get_random_unicode(length):
+    """Adapted from <https://stackoverflow.com/a/21666621>"""
+
+    try:
+        get_char = unichr
+    except NameError:
+        get_char = chr
+
+    # code point ranges to be sampled
+    include_ranges = [
+        # ASCII non-control characters excluding single quote (0x27) and backslash (0x5c)
+        (0x20, 0x26), (0x28, 0x5b), (0x5d, 0x7e)
+    ]
+
+    alphabet = [
+        get_char(code_point) for current_range in include_ranges
+            for code_point in range(current_range[0], current_range[1] + 1)
+    ]
+    return ''.join(random.choice(alphabet) for _ in range(length))
+
+
+if __name__ == "__main__":
+    for i in range(10):
+        print('>' + get_random_unicode(5))
+        print("ATGC")
+

tests/functional/tree/cram/iqtree-name-modifications.t

@@ -84,3 +84,21 @@ similar to single quotes.
   Invalid characters: .* (re)
 
   [2]
+
+This test generates random ASCII names. It's disabled for CI as it's both
+stochastic and slow but you can easily toggle it back on (by uncommenting the
+function call) if you want to better test strain name handling in `augur tree`
+
+  $ random_ascii_names() {
+  >   python3 "$TESTDIR"/generate-fasta.py > random_${1}.mfa
+  >  
+  >   ${AUGUR} tree \
+  >    --method iqtree \
+  >    --alignment random_${1}.mfa \
+  >    --output random_${1}.new > /dev/null
+  > }
+
+  $ for iteration in $(seq 1 100); do
+  >    # random_ascii_names $iteration
+  >    :
+  > done