tests: make doctests suite run with old ghcs

(Require a newer doctest which supports --fast and --verbose.)

hledger-lib/package.yaml

@@ -156,14 +156,19 @@ tests:
     source-dirs: test
     dependencies:
     - Glob >=0.7
-    - doctest >=0.8
+    # Use a doctest new enough to support --fast and --verbose.
-    # doctest >=0.16.0 needed to show verbose progress output
+    - doctest >=0.16
-    # doctest with ghc 8.4 on mac requires a workaround:
+    # Note: doctest with ghc 8.4+ on mac breaks, needs this workaround:
     #  ~$ locate HSinteger-gmp-1.0.2.0.o
     #  /Users/simon/.stack/programs/x86_64-osx/ghc-8.4.3/lib/ghc-8.4.2/integer-gmp-1.0.2.0/HSinteger-gmp-1.0.2.0.o
     #  ~$ mv /Users/simon/.stack/programs/x86_64-osx/ghc-8.4.3/lib/ghc-8.4.2/integer-gmp-1.0.2.0/HSinteger-gmp-1.0.2.0.o{,_DISABLE_GHC_ISSUE_15105}
     # See https://github.com/sol/doctest/issues/199,
-    # https://ghc.haskell.org/trac/ghc/ticket/15105#comment:10
+    # https://ghc.haskell.org/trac/ghc/ticket/15105#comment:10 .
+    # Should probably disable it by default, but I think my testing convenience
+    # outweighs the small number of folks who'll hit this.. if I'm wrong let me know.
+    #when:
+    # - condition: os(darwin) && impl(ghc >= 8.4)
+    #   buildable: false
 
   easytests:
     main: easytests.hs

hledger-lib/test/doctests.hs

@@ -58,6 +58,6 @@ main = do
     when verbose $ putStrLn $ unwords fs
 
     doctest $
-      (if verbose then ("--verbose" :) else id) $ 
+      (if verbose then ("--verbose" :) else id) $  -- doctest >= 0.15.0
-      (if slow then id else ("--fast" :)) $
+      (if slow then id else ("--fast" :)) $        -- doctest >= 0.11.4
       fs

stack-ghc7.10.yaml

@@ -30,6 +30,7 @@ extra-deps:
 - criterion-1.4.1.0
 - data-clist-0.1.2.1
 - directory-1.2.7.0
+- doctest-0.16.0
 - exceptions-0.10.0
 - free-5.0.2
 - generics-sop-0.3.2.0

stack-ghc8.0.yaml

@@ -21,6 +21,7 @@ extra-deps:
 - base-compat-batteries-0.10.1
 - bifunctors-5.5.2
 - criterion-1.4.1.0
+- doctest-0.16.0
 - generics-sop-0.3.2.0
 - hashable-1.2.7.0
 - http-media-0.7.1.2

stack-ghc8.2.yaml

@@ -16,6 +16,7 @@ extra-deps:
 - base-compat-0.10.1
 - base-compat-batteries-0.10.1
 - criterion-1.4.1.0
+- doctest-0.16.0
 - swagger2-2.2.2
 # avoid no hashable instance for AccountName from doctests
 - hashtables-1.2.3.1