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nixpkgs/lib/tests/misc.nix
Profpatsch 8252861507 lib/trivial: add pipe function
`pipe` is a useful operator for creating pipelines of functions.

It works around the usual problem of e.g. string operations becoming
deeply nested functions.

In principle, there are four different ways this function could be
written:

pipe val [ f1 .. fn ]
pipe val [ fn .. f1 ]
compose [ f1 .. fn ] val
compose [ fn .. f1 ] val

The third and fourth form mirror composition of functions, they would
be the same as e.g. `(f1 << f2 << f3 .. << fn) val`.
However, it is not clear which direction the list should have (as one
can see in the second form, which is the most absurd.

In order not to confuse users, we decide for the most “intuitive”
form, which mirrors the way unix pipes work (thus the name `pipe`).
The flow of data goes from left to right.

Co-Authored-By: Silvan Mosberger <infinisil@icloud.com>
2019-10-21 13:19:16 +02:00

445 lines
9.6 KiB
Nix

# to run these tests:
# nix-instantiate --eval --strict nixpkgs/lib/tests/misc.nix
# if the resulting list is empty, all tests passed
with import ../default.nix;
runTests {
# TRIVIAL
testId = {
expr = id 1;
expected = 1;
};
testConst = {
expr = const 2 3;
expected = 2;
};
testPipe = {
expr = pipe 2 [
(x: x + 2) # 2 + 2 = 4
(x: x * 2) # 4 * 2 = 8
];
expected = 8;
};
testPipeEmpty = {
expr = pipe 2 [];
expected = 2;
};
testPipeStrings = {
expr = pipe [ 3 4 ] [
(map toString)
(map (s: s + "\n"))
concatStrings
];
expected = ''
3
4
'';
};
/*
testOr = {
expr = or true false;
expected = true;
};
*/
testAnd = {
expr = and true false;
expected = false;
};
testFix = {
expr = fix (x: {a = if x ? a then "a" else "b";});
expected = {a = "a";};
};
testComposeExtensions = {
expr = let obj = makeExtensible (self: { foo = self.bar; });
f = self: super: { bar = false; baz = true; };
g = self: super: { bar = super.baz or false; };
f_o_g = composeExtensions f g;
composed = obj.extend f_o_g;
in composed.foo;
expected = true;
};
testBitAnd = {
expr = (bitAnd 3 10);
expected = 2;
};
testBitOr = {
expr = (bitOr 3 10);
expected = 11;
};
testBitXor = {
expr = (bitXor 3 10);
expected = 9;
};
# STRINGS
testConcatMapStrings = {
expr = concatMapStrings (x: x + ";") ["a" "b" "c"];
expected = "a;b;c;";
};
testConcatStringsSep = {
expr = concatStringsSep "," ["a" "b" "c"];
expected = "a,b,c";
};
testSplitStringsSimple = {
expr = strings.splitString "." "a.b.c.d";
expected = [ "a" "b" "c" "d" ];
};
testSplitStringsEmpty = {
expr = strings.splitString "." "a..b";
expected = [ "a" "" "b" ];
};
testSplitStringsOne = {
expr = strings.splitString ":" "a.b";
expected = [ "a.b" ];
};
testSplitStringsNone = {
expr = strings.splitString "." "";
expected = [ "" ];
};
testSplitStringsFirstEmpty = {
expr = strings.splitString "/" "/a/b/c";
expected = [ "" "a" "b" "c" ];
};
testSplitStringsLastEmpty = {
expr = strings.splitString ":" "2001:db8:0:0042::8a2e:370:";
expected = [ "2001" "db8" "0" "0042" "" "8a2e" "370" "" ];
};
testSplitVersionSingle = {
expr = versions.splitVersion "1";
expected = [ "1" ];
};
testSplitVersionDouble = {
expr = versions.splitVersion "1.2";
expected = [ "1" "2" ];
};
testSplitVersionTriple = {
expr = versions.splitVersion "1.2.3";
expected = [ "1" "2" "3" ];
};
testIsStorePath = {
expr =
let goodPath =
"${builtins.storeDir}/d945ibfx9x185xf04b890y4f9g3cbb63-python-2.7.11";
in {
storePath = isStorePath goodPath;
storePathDerivation = isStorePath (import ../.. {}).hello;
storePathAppendix = isStorePath
"${goodPath}/bin/python";
nonAbsolute = isStorePath (concatStrings (tail (stringToCharacters goodPath)));
asPath = isStorePath (/. + goodPath);
otherPath = isStorePath "/something/else";
otherVals = {
attrset = isStorePath {};
list = isStorePath [];
int = isStorePath 42;
};
};
expected = {
storePath = true;
storePathDerivation = true;
storePathAppendix = false;
nonAbsolute = false;
asPath = true;
otherPath = false;
otherVals = {
attrset = false;
list = false;
int = false;
};
};
};
# LISTS
testFilter = {
expr = filter (x: x != "a") ["a" "b" "c" "a"];
expected = ["b" "c"];
};
testFold =
let
f = op: fold: fold op 0 (range 0 100);
# fold with associative operator
assoc = f builtins.add;
# fold with non-associative operator
nonAssoc = f builtins.sub;
in {
expr = {
assocRight = assoc foldr;
# right fold with assoc operator is same as left fold
assocRightIsLeft = assoc foldr == assoc foldl;
nonAssocRight = nonAssoc foldr;
nonAssocLeft = nonAssoc foldl;
# with non-assoc operator the fold results are not the same
nonAssocRightIsNotLeft = nonAssoc foldl != nonAssoc foldr;
# fold is an alias for foldr
foldIsRight = nonAssoc fold == nonAssoc foldr;
};
expected = {
assocRight = 5050;
assocRightIsLeft = true;
nonAssocRight = 50;
nonAssocLeft = (-5050);
nonAssocRightIsNotLeft = true;
foldIsRight = true;
};
};
testTake = testAllTrue [
([] == (take 0 [ 1 2 3 ]))
([1] == (take 1 [ 1 2 3 ]))
([ 1 2 ] == (take 2 [ 1 2 3 ]))
([ 1 2 3 ] == (take 3 [ 1 2 3 ]))
([ 1 2 3 ] == (take 4 [ 1 2 3 ]))
];
testFoldAttrs = {
expr = foldAttrs (n: a: [n] ++ a) [] [
{ a = 2; b = 7; }
{ a = 3; c = 8; }
];
expected = { a = [ 2 3 ]; b = [7]; c = [8];};
};
testSort = {
expr = sort builtins.lessThan [ 40 2 30 42 ];
expected = [2 30 40 42];
};
testToIntShouldConvertStringToInt = {
expr = toInt "27";
expected = 27;
};
testToIntShouldThrowErrorIfItCouldNotConvertToInt = {
expr = builtins.tryEval (toInt "\"foo\"");
expected = { success = false; value = false; };
};
testHasAttrByPathTrue = {
expr = hasAttrByPath ["a" "b"] { a = { b = "yey"; }; };
expected = true;
};
testHasAttrByPathFalse = {
expr = hasAttrByPath ["a" "b"] { a = { c = "yey"; }; };
expected = false;
};
# ATTRSETS
# code from the example
testRecursiveUpdateUntil = {
expr = recursiveUpdateUntil (path: l: r: path == ["foo"]) {
# first attribute set
foo.bar = 1;
foo.baz = 2;
bar = 3;
} {
#second attribute set
foo.bar = 1;
foo.quz = 2;
baz = 4;
};
expected = {
foo.bar = 1; # 'foo.*' from the second set
foo.quz = 2; #
bar = 3; # 'bar' from the first set
baz = 4; # 'baz' from the second set
};
};
testOverrideExistingEmpty = {
expr = overrideExisting {} { a = 1; };
expected = {};
};
testOverrideExistingDisjoint = {
expr = overrideExisting { b = 2; } { a = 1; };
expected = { b = 2; };
};
testOverrideExistingOverride = {
expr = overrideExisting { a = 3; b = 2; } { a = 1; };
expected = { a = 1; b = 2; };
};
# GENERATORS
# these tests assume attributes are converted to lists
# in alphabetical order
testMkKeyValueDefault = {
expr = generators.mkKeyValueDefault {} ":" "f:oo" "bar";
expected = ''f\:oo:bar'';
};
testMkValueString = {
expr = let
vals = {
int = 42;
string = ''fo"o'';
bool = true;
bool2 = false;
null = null;
# float = 42.23; # floats are strange
};
in mapAttrs
(const (generators.mkValueStringDefault {}))
vals;
expected = {
int = "42";
string = ''fo"o'';
bool = "true";
bool2 = "false";
null = "null";
# float = "42.23" true false [ "bar" ] ]'';
};
};
testToKeyValue = {
expr = generators.toKeyValue {} {
key = "value";
"other=key" = "baz";
};
expected = ''
key=value
other\=key=baz
'';
};
testToINIEmpty = {
expr = generators.toINI {} {};
expected = "";
};
testToINIEmptySection = {
expr = generators.toINI {} { foo = {}; bar = {}; };
expected = ''
[bar]
[foo]
'';
};
testToINIDefaultEscapes = {
expr = generators.toINI {} {
"no [ and ] allowed unescaped" = {
"and also no = in keys" = 42;
};
};
expected = ''
[no \[ and \] allowed unescaped]
and also no \= in keys=42
'';
};
testToINIDefaultFull = {
expr = generators.toINI {} {
"section 1" = {
attribute1 = 5;
x = "Me-se JarJar Binx";
# booleans are converted verbatim by default
boolean = false;
};
"foo[]" = {
"he\\h=he" = "this is okay";
};
};
expected = ''
[foo\[\]]
he\h\=he=this is okay
[section 1]
attribute1=5
boolean=false
x=Me-se JarJar Binx
'';
};
/* right now only invocation check */
testToJSONSimple =
let val = {
foobar = [ "baz" 1 2 3 ];
};
in {
expr = generators.toJSON {} val;
# trivial implementation
expected = builtins.toJSON val;
};
/* right now only invocation check */
testToYAMLSimple =
let val = {
list = [ { one = 1; } { two = 2; } ];
all = 42;
};
in {
expr = generators.toYAML {} val;
# trivial implementation
expected = builtins.toJSON val;
};
testToPretty = {
expr = mapAttrs (const (generators.toPretty {})) rec {
int = 42;
float = 0.1337;
bool = true;
string = ''fno"rd'';
path = /. + "/foo";
null_ = null;
function = x: x;
functionArgs = { arg ? 4, foo }: arg;
list = [ 3 4 function [ false ] ];
attrs = { foo = null; "foo bar" = "baz"; };
drv = derivation { name = "test"; system = builtins.currentSystem; };
};
expected = rec {
int = "42";
float = "~0.133700";
bool = "true";
string = ''"fno\"rd"'';
path = "/foo";
null_ = "null";
function = "<λ>";
functionArgs = "<λ:{(arg),foo}>";
list = "[ 3 4 ${function} [ false ] ]";
attrs = "{ \"foo\" = null; \"foo bar\" = \"baz\"; }";
drv = "<δ:test>";
};
};
testToPrettyAllowPrettyValues = {
expr = generators.toPretty { allowPrettyValues = true; }
{ __pretty = v: "«" + v + "»"; val = "foo"; };
expected = "«foo»";
};
}