mirror of
https://github.com/jfmengels/elm-review.git
synced 2024-12-23 17:53:35 +03:00
558 lines
17 KiB
Elm
558 lines
17 KiB
Elm
module CognitiveComplexityTest exposing (all)
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import CognitiveComplexity exposing (rule)
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import Elm.Syntax.Range exposing (Range)
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import Expect exposing (Expectation)
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import Review.Test
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import Test exposing (Test, describe, test)
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all : Test
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all =
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describe "CognitiveComplexity"
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[ test "should not report an error when the complexity is lower than the threshold" <|
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\() ->
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"""module A exposing (..)
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a = 1
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"""
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|> Review.Test.run (rule 1)
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|> Review.Test.expectNoErrors
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, test "should report an error when the complexity is higher than the threshold" <|
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\() ->
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"""module A exposing (..)
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fun n =
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if cond then -- +1
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if cond then -- +2
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if cond then -- +3
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if cond then -- +4
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1
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else
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2
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else
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2
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else
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2
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else
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2
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"""
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|> expect
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[ { name = "fun"
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, complexity = 10
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, details = [ String.trim """
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Line 3: +1 for the if expression
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Line 4: +2 for the if expression (including 1 for nesting)
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Line 5: +3 for the if expression (including 2 for nesting)
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Line 6: +4 for the if expression (including 3 for nesting)
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""" ]
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}
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]
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, test "should count a simple value or operation as 0" <|
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\() ->
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"""module A exposing (..)
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fun n =
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n + 1
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"""
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|> expect [ { name = "fun", complexity = 0, details = [] } ]
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, test "should count if expression as 1" <|
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\() ->
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"""module A exposing (..)
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fun n =
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if cond then
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1
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else
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2
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"""
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|> expect
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[ { name = "fun"
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, complexity = 1
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, details = [ "Line 3: +1 for the if expression" ]
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}
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]
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, test "should count if else expressions" <|
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\() ->
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"""module A exposing (..)
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fun n =
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if cond then -- +1
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1
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else if cond then -- +1
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2
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else
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2
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"""
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|> expect
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[ { name = "fun"
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, complexity = 2
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, details = [ String.trim """
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Line 3: +1 for the if expression
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Line 5: +1 for the else if expression
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""" ]
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}
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]
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, test "should properly decrement when exiting else expression" <|
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\() ->
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"""module A exposing (..)
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fun n =
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let
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_ =
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if cond then -- +1
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1
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else if cond then -- +1
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2
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else
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3
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in
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if cond then -- +1
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4
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else
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5
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"""
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|> expect
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[ { name = "fun"
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, complexity = 3
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, details = [ String.trim """
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Line 5: +1 for the if expression
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Line 7: +1 for the else if expression
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Line 12: +1 for the if expression
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""" ]
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}
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]
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, test "should increment nesting when inside a let function" <|
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\() ->
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"""module A exposing (..)
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fun n =
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let
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fn n =
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if cond then -- +2
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1
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else
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2
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in
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fn n
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"""
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|> expect
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[ { name = "fun"
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, complexity = 2
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, details = [ String.trim """
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Line 5: +2 for the if expression (including 1 for nesting)
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""" ]
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}
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]
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, test "should properly decrement nesting when exiting a let function" <|
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\() ->
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"""module A exposing (..)
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fun n =
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let
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fn1 n = -- nesting increment
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1
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fn2 =
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if cond then -- +1
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1
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else
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2
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in
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1
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"""
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|> expect
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[ { name = "fun"
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, complexity = 1
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, details = [ String.trim """
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Line 8: +1 for the if expression
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""" ]
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}
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]
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, test "should count case expression as 1" <|
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\() ->
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"""module A exposing (..)
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fun n =
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case n of -- +1
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1 -> ()
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2 -> ()
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3 -> ()
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4 -> ()
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_ -> ()
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"""
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|> expect
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[ { name = "fun"
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, complexity = 1
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, details = [ "Line 3: +1 for the case expression" ]
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}
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]
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, test "should count nesting of case expressions" <|
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\() ->
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"""module A exposing (..)
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fun n =
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case n of -- +1
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1 -> ()
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2 -> ()
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3 -> case n of -- +2
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_ -> ()
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4 -> ()
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_ -> ()
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"""
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|> expect
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[ { name = "fun"
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, complexity = 3
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, details = [ String.trim """
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Line 3: +1 for the case expression
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Line 6: +2 for the case expression (including 1 for nesting)
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""" ]
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}
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]
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, test "should decrement the nesting when leaving a nested structure" <|
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\() ->
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"""module A exposing (..)
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fun n =
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if cond then -- +1
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if cond then -- +2
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if cond then -- +3
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1
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else
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2
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else
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2
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else
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case n of -- +2
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() -> ()
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"""
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|> expect
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[ { name = "fun"
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, complexity = 8
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, details = [ String.trim """
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Line 3: +1 for the if expression
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Line 4: +2 for the if expression (including 1 for nesting)
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Line 5: +3 for the if expression (including 2 for nesting)
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Line 12: +2 for the case expression (including 1 for nesting)
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""" ]
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}
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]
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, test "should increment once when using the && boolean operator" <|
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\() ->
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"""module A exposing (..)
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fun n =
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if -- +1
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a && b && c && d -- +1 for the usage of &&
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then
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1
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else
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2
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"""
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|> expect
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[ { name = "fun"
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, complexity = 2
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, details = [ String.trim """
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Line 3: +1 for the if expression
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Line 4: +1 for the use of `&&`
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""" ]
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}
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]
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, test "should increment once when using the || boolean operator" <|
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\() ->
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"""module A exposing (..)
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fun n =
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if -- +1
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a || b || c || d -- +1 for the usage of ||
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then
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1
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else
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2
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"""
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|> expect
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[ { name = "fun"
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, complexity = 2
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, details = [ String.trim """
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Line 3: +1 for the if expression
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Line 4: +1 for the use of `||`
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""" ]
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}
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]
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, test "should increment when mixing boolean operators" <|
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\() ->
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"""module A exposing (..)
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fun n =
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if -- +1
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a && b && c -- +1
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|| d || e -- +1
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&& f -- +1
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then
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1
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else
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2
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"""
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|> expect
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[ { name = "fun"
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, complexity = 4
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, details = [ String.trim """
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Line 3: +1 for the if expression
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Line 4: +1 for the use of `||`
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Line 4: +1 for the use of `&&`
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Line 5: +1 for the use of `&&`
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""" ]
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}
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]
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, test "should not increment for anonymous functions" <|
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\() ->
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"""module A exposing (..)
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fun n =
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List.map (\\m -> m + 1) n
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"""
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|> expect
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[ { name = "fun"
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, complexity = 0
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, details = []
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}
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]
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, test "should increment the nesting inside anonymous functions" <|
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\() ->
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"""module A exposing (..)
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fun n =
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List.map
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(\\m ->
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if cond then -- +2
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1
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else
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2
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)
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n
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"""
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|> expect
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[ { name = "fun"
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, complexity = 2
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, details = [ "Line 5: +2 for the if expression (including 1 for nesting)" ]
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}
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]
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, test "should properly decrement the nesting when exiting an anonymous function" <|
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\() ->
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"""module A exposing (..)
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fun n =
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let
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_ = List.map (\\m -> m + 1) n
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in
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if cond then -- +1
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1
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else
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2
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"""
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|> expect
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[ { name = "fun"
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, complexity = 1
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, details = [ "Line 6: +1 for the if expression" ]
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}
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]
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, test "should increment when finding a recursive call" <|
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\() ->
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"""module A exposing (..)
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fun n =
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if n > 0 then -- +1
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1 + fun (n - 1) -- +1
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else
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1
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"""
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|> expectAtExactly
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[ { name = "fun"
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, complexity = 2
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, atExactly = { start = { row = 2, column = 1 }, end = { row = 2, column = 4 } }
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, details = [ String.trim """
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Line 3: +1 for the if expression
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Line 4: +1 for the recursive call
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""" ]
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}
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]
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, test "should only increment once, even if there are multiple recursive calls" <|
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\() ->
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"""module A exposing (..)
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fib n =
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if n > 0 then -- +1
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fib (n - 1) -- +1
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+ fib (n - 2) -- +0
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else
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0
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"""
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|> expectAtExactly
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[ { name = "fib"
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, complexity = 2
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, atExactly = { start = { row = 2, column = 1 }, end = { row = 2, column = 4 } }
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, details = [ String.trim """
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Line 3: +1 for the if expression
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Line 4: +1 for the recursive call
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""" ]
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}
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]
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, test "should increment the complexity for every recursive call in a chain" <|
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\() ->
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"""module A exposing (..)
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fun1 n = -- +1
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fun2 n
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fun2 n = -- +1
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fun1 n
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"""
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|> expectAtExactly
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[ { name = "fun1"
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, complexity = 1
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, atExactly = { start = { row = 2, column = 1 }, end = { row = 2, column = 5 } }
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, details = [ String.trim """
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Line 3: +1 for the indirect recursive call to fun2
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""" ]
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}
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, { name = "fun2"
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, complexity = 1
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, atExactly = { start = { row = 5, column = 1 }, end = { row = 5, column = 5 } }
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, details = [ String.trim """
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Line 6: +1 for the indirect recursive call to fun1
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""" ]
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}
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]
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, test "should increment the complexity for every recursive call in a chain, for each different function call" <|
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\() ->
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"""module A exposing (..)
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fun1 n =
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fun2 n -- +1
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+ fun2 n -- +0, already counted
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+ fun1 n -- +1
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fun2 n =
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fun1 n -- +1
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"""
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|> expectAtExactly
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[ { name = "fun1"
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, complexity = 2
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, atExactly = { start = { row = 2, column = 1 }, end = { row = 2, column = 5 } }
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, details =
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[ String.trim """
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Line 3: +1 for the indirect recursive call to fun2
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Line 5: +1 for the recursive call
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"""
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]
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}
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, { name = "fun2"
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, complexity = 1
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, atExactly = { start = { row = 7, column = 1 }, end = { row = 7, column = 5 } }
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, details = [ String.trim """
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Line 8: +1 for the indirect recursive call to fun1
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""" ]
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}
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]
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, test "should increment the complexity for every recursive call in a chain, for long chains" <|
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\() ->
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"""module A exposing (..)
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fun1 n =
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fun2 n -- +1
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fun2 n =
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fun3 n -- +1
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fun3 n =
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fun4 n -- +1
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fun4 n =
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fun5 n -- +1
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fun5 n =
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fun1 n -- +1
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"""
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|> expectAtExactly
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[ { name = "fun1"
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, complexity = 1
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, atExactly = { start = { row = 2, column = 1 }, end = { row = 2, column = 5 } }
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, details = [ "Line 3: +1 for the indirect recursive call to fun2" ]
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}
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, { name = "fun2"
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, complexity = 1
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, atExactly = { start = { row = 4, column = 1 }, end = { row = 4, column = 5 } }
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, details = [ "Line 5: +1 for the indirect recursive call to fun3" ]
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}
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, { name = "fun3"
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, complexity = 1
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, atExactly = { start = { row = 6, column = 1 }, end = { row = 6, column = 5 } }
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, details = [ "Line 7: +1 for the indirect recursive call to fun4" ]
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}
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, { name = "fun4"
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, complexity = 1
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, atExactly = { start = { row = 8, column = 1 }, end = { row = 8, column = 5 } }
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, details = [ "Line 9: +1 for the indirect recursive call to fun5" ]
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}
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, { name = "fun5"
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, complexity = 1
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, atExactly = { start = { row = 10, column = 1 }, end = { row = 10, column = 5 } }
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, details = [ "Line 11: +1 for the indirect recursive call to fun1" ]
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}
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]
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, test "the complexity of a function should not affect another function's computed complexity" <|
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\() ->
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"""module A exposing (..)
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simple n = 1
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fun n =
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if cond then
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if cond then
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1
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else
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2
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else
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2
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alsoSimple n =
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if cond then
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1
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else
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2
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"""
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|> expect
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[ { name = "simple"
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, complexity = 0
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, details = []
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}
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, { name = "fun"
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, complexity = 3
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, details = [ String.trim """
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Line 5: +1 for the if expression
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Line 6: +2 for the if expression (including 1 for nesting)
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""" ]
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}
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, { name = "alsoSimple"
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, complexity = 1
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, details = [ "Line 14: +1 for the if expression" ]
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}
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]
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]
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expect : List { name : String, complexity : Int, details : List String } -> String -> Expectation
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expect functionComplexities source =
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source
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|> Review.Test.run (rule -1)
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|> Review.Test.expectErrors
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(List.map
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(\{ name, complexity, details } ->
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Review.Test.error
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{ message = name ++ " has a cognitive complexity of " ++ String.fromInt complexity ++ ", higher than the allowed -1"
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, details = explanation ++ details
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, under = name
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}
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)
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functionComplexities
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)
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expectAtExactly : List { name : String, complexity : Int, details : List String, atExactly : Range } -> String -> Expectation
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expectAtExactly functionComplexities source =
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source
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|> Review.Test.run (rule -1)
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|> Review.Test.expectErrors
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(List.map
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(\{ name, complexity, details, atExactly } ->
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Review.Test.error
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{ message = name ++ " has a cognitive complexity of " ++ String.fromInt complexity ++ ", higher than the allowed -1"
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, details = explanation ++ details
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, under = name
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}
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|> Review.Test.atExactly atExactly
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)
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functionComplexities
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)
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explanation : List String
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explanation =
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[ "This metric is a heuristic to measure how easy to understand a piece of code is, primarily through increments for breaks in the linear flow and for nesting those breaks."
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, "The most common ways to reduce complexity is to extract sections into functions and to unnest control flow structures. Following is a breakdown of where complexity was found:"
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]
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