mapreduce| Adds map/reduce functionality to SimilarChecker

Before adding a new mixin this proves the concept works, adding tests as
examples of how this would work in the main linter.

The idea here is that, because `check_parallel()` uses a multiprocess
`map` function, that the natural follow on is to use a 'reduce`
paradigm. This should demonstrate that.

2 files changed, 99 insertions, 0 deletions

diff --git a/tests/input/similar_lines_a.py b/tests/input/similar_lines_a.py
new file mode 100644
index 000000000..65a72a79d
--- /dev/null
+++ b/tests/input/similar_lines_a.py
@@ -0,0 +1,63 @@
+""" A file designed to have lines of similarity when compared to similar_lines_b
+
+We use lorm-ipsum to generate 'random' code. """
+# Copyright (c) 2020 Frank Harrison <frank@doublethefish.com>
+
+
+def adipiscing(elit):
+    etiam = "id"
+    dictum = "purus,"
+    vitae = "pretium"
+    neque = "Vivamus"
+    nec = "ornare"
+    tortor = "sit"
+    return etiam, dictum, vitae, neque, nec, tortor
+
+
+class Amet:
+    def similar_function_3_lines(self, tellus):  # line same #1
+        agittis = 10  # line same #2
+        tellus *= 300  # line same #3
+        return agittis, tellus  # line diff
+
+    def lorem(self, ipsum):
+        dolor = "sit"
+        amet = "consectetur"
+        return (lorem, dolor, amet)
+
+    def similar_function_5_lines(self, similar):  # line same #1
+        some_var = 10  # line same #2
+        someother_var *= 300  # line same #3
+        fusce = "sit"  # line same #4
+        amet = "tortor"  # line same #5
+        return some_var, someother_var, fusce, amet  # line diff
+
+    def __init__(self, moleskie, lectus="Mauris", ac="pellentesque"):
+        metus = "ut"
+        lobortis = "urna."
+        Integer = "nisl"
+        (mauris,) = "interdum"
+        non = "odio"
+        semper = "aliquam"
+        malesuada = "nunc."
+        iaculis = "dolor"
+        facilisis = "ultrices"
+        vitae = "ut."
+
+        return (
+            metus,
+            lobortis,
+            Integer,
+            mauris,
+            non,
+            semper,
+            malesuada,
+            iaculis,
+            facilisis,
+            vitae,
+        )
+
+    def similar_function_3_lines(self, tellus):  # line same #1
+        agittis = 10  # line same #2
+        tellus *= 300  # line same #3
+        return agittis, tellus  # line diff
diff --git a/tests/input/similar_lines_b.py b/tests/input/similar_lines_b.py
new file mode 100644
index 000000000..21634883d
--- /dev/null
+++ b/tests/input/similar_lines_b.py
@@ -0,0 +1,36 @@
+""" The sister file of similar_lines_a, another file designed to have lines of
+similarity when compared to its sister file
+
+As with the sister file, we use lorm-ipsum to generate 'random' code. """
+# Copyright (c) 2020 Frank Harrison <frank@doublethefish.com>
+
+
+class Nulla:
+    tortor = "ultrices quis porta in"
+    sagittis = "ut tellus"
+
+    def pulvinar(self, blandit, metus):
+        egestas = [mauris for mauris in zip(blandit, metus)]
+        neque = (egestas, blandit)
+
+    def similar_function_5_lines(self, similar):  # line same #1
+        some_var = 10  # line same #2
+        someother_var *= 300  # line same #3
+        fusce = "sit"  # line same #4
+        amet = "tortor"  # line same #5
+        iaculis = "dolor"  # line diff
+        return some_var, someother_var, fusce, amet, iaculis, iaculis  # line diff
+
+
+def tortor(self):
+    ultrices = 2
+    quis = ultricies * "porta"
+    return ultricies, quis
+
+
+class Commodo:
+    def similar_function_3_lines(self, tellus):  # line same #1
+        agittis = 10  # line same #2
+        tellus *= 300  # line same #3
+        laoreet = "commodo "  # line diff
+        return agittis, tellus, laoreet  # line diff