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the kind of programming
Apr. 7th, 2019 10:25 pmReminds me what we did in Forth, with Leo, present here:
This is a test case. Rather, 25 test cases.
We scan through
and then, in each row, apply this representable to objects
But toposes are not essential here. I just decided to be lazy, and write code as tables, as Leo suggested eons ago, probably in 1989. It's not even my idea.
Implementation:
applyTo | "a" | "b" | "c" | "d" | "e" |
at("a") | "a" | "ab" | "" | "" | "" |
at("b") | "" | "b" | "" | "" | "" |
at("c") | "" | "cb" | "c" | "cd" | "" |
at("d") | "" | "" | "" | "d" | "" |
at("e") | "" | "" | "" | "ed" | "e"
This is a test case. Rather, 25 test cases.
We scan through
at("a") to at("e"), where at(x) is a representable diagram (presheaf, functor, whatever) for object x:
val at = (obj: topos.site.Obj) => topos.representable(obj)
and then, in each row, apply this representable to objects
"a",..., "e", and check that the result is a set (hom(x, y)) consisting of the values in the cells of the table. The values in the table are split by comma and converted to sets - because we deal with Grothendieck toposes.But toposes are not essential here. I just decided to be lazy, and write code as tables, as Leo suggested eons ago, probably in 1989. It's not even my idea.
Implementation:
val at = (obj: topos.site.Obj) => topos.representable(obj)
case class table(data: List[String] = Nil) {
def |(x: String): table = table(x::data)
def |(d: Diagrams.Diagram) = check(d, data, data)
}
case class check(d: Diagram, data: List[String], fullList: List[String]) {
def |(x: String): check = {
d(data.head) === x.split(",").toSet
check(d, data.tail, fullList)
}
def |(d: Diagram): check = check(d, fullList, fullList)
}
val applyTo = new table
a little song I wrote
Aug. 28th, 2015 11:42 am
def write2DB[T <: {def save(): Boolean }](t:T): Result[T] =
if (t.save()) Good(t) else Result.error(s"Failed to save $t")
The trick is, never call
save(), because it involves implicits etc. Call write2DB. Mock this function in your unittests.Just wrote a couple of methods in my main mock class.
and most of the methods look like this:
Now in the test I write stuff like this:
... do you need explanations on how it works?
What I personally enjoy here is the leisure JavaScript coding style, where you just join the arguments, not giving a fuck about their types.
public void failingOn(String regex) {
this.failureCondition = regex;
}
public void maybeFail(Object...objects) throws HBaseException {
if (failureCondition != null) {
String s = Arrays.asList(objects).toString();
if (s.matches(failureCondition)) {
throw new HBaseException("Congratulations, you hit the jackpot today: " + s);
}
}
}
and most of the methods look like this:
@Override public void bulkDelete(String tableName, CollectionrowKeys, String columnFamily) throws HBaseException { maybeFail("bulkDelete", tableName, rowKeys, columnFamily); table(tableName).family(columnFamily).delete(rowKeys); }
Now in the test I write stuff like this:
@Test
public void testPut_replicating_withErrors() throws Exception {
MockHBaseOperations cluster2 = new MockHBaseOperations();
cluster2.failingOn("\\[sendToCluster, BadTable,.*");
...
}
... do you need explanations on how it works?
What I personally enjoy here is the leisure JavaScript coding style, where you just join the arguments, not giving a fuck about their types.
