builtins_test.go

@@ -4,13 +4,11 @@ import (
 	"encoding/base64"
 	"fmt"
 	"regexp"
-	"slices"
 	"strconv"
 	"strings"
 	"testing"
 	"time"
 
-	"github.com/larvit/fejkdata/internal/grammar"
 )
 
 func TestBuiltinIDGenerators(t *testing.T) {
@@ -191,31 +189,6 @@ func ibanValid(s string) bool {
 	return rem == 1
 }
 
-// TestRegistryShapes pins the builtin contract compileFormat relies on: every entry
-// supplies prep, and args parsed at compile only behind a check.
-func TestRegistryShapes(t *testing.T) {
-	for name, b := range builtins {
-		if b.prep == nil {
-			t.Errorf("builtin %q has no prep: compileFormat would call a nil func", name)
-		}
-		if b.arity != 0 && b.checkArgs == nil {
-			t.Errorf("builtin %q parses args in prep with no check", name)
-		}
-	}
-}
-
-// TestArgGuardsPanic pins the guards that report a builtin arg its check should
-// have rejected. No data reaches them — checkFunc runs a builtin's check before
-// compileFormat ever calls prep — so they are exercised directly.
-func TestArgGuardsPanic(t *testing.T) {
-	for name, call := range map[string]func(){
-		"atoi on an unvalidated arg": func() { atoi("nope") },
-		"atof on an unvalidated arg": func() { atof("nope") },
-	} {
-		mustPanic(t, name, call)
-	}
-}
-
 // mustPanic fails unless call panics with internalError's phrase, which is what
 // separates a reported invariant break from a silently wrong value.
 func mustPanic(t *testing.T, name string, call func()) {
@@ -450,14 +423,3 @@ func TestArgErrorsNameTheSpelling(t *testing.T) {
 		}
 	}
 }
-
-func TestNoRefOperandsMatchesTheOperandGrammar(t *testing.T) {
-	for name, b := range builtins {
-		if b.operands == nil {
-			continue
-		}
-		if takesRef := slices.ContainsFunc(b.operands([]string{"/x"}), grammar.IsRef); b.noRefOperands == takesRef {
-			t.Errorf("%s: noRefOperands = %v, but its operands func reads a reference: %v", name, b.noRefOperands, takesRef)
-		}
-	}
-}

calc_test.go

@@ -113,12 +113,6 @@ func TestParsedCallReadsOnlyAnOperandBuiltin(t *testing.T) {
 	}
 }
 
-// TestCalcPrepPanicsOnAnUncheckedExpression pins the guard on calc's own invariant:
-// checkCalc parsed the expression before prep sees it.
-func TestCalcPrepPanicsOnAnUncheckedExpression(t *testing.T) {
-	mustPanic(t, "prep on an expression that does not parse", func() { calcPrep([]string{"1 +"}) })
-}
-
 // --- one draw, one value: a calc operand reads the expansion's draw ---
 
 // TestANamedCalcOperandIsTheOneShown pins how a calc computes from the value its format

imports_test.go

@@ -29,10 +29,14 @@ func TestPackageImports(t *testing.T) {
 	}
 	checked := 0
 	allowed := map[string][]string{
-		".":                  {"internal/drawstate", "internal/grammar"},
-		"cmd/fejkdata":       {"."},
-		"internal/drawstate": nil,
-		"internal/grammar":   nil,
+		".":                    {"internal/builtinfunc", "internal/datafiles", "internal/datatype", "internal/drawstate", "internal/grammar", "internal/proven"},
+		"cmd/fejkdata":         {"."},
+		"internal/builtinfunc": {"internal/datatype", "internal/drawstate", "internal/grammar", "internal/proven"},
+		"internal/datafiles":   {"internal/grammar"},
+		"internal/datatype":    nil,
+		"internal/drawstate":   nil,
+		"internal/grammar":     nil,
+		"internal/proven":      {"internal/datatype", "internal/grammar"},
 	}
 	seen := map[string]bool{}
 	err = filepath.WalkDir(".", func(dir string, d fs.DirEntry, err error) error {

internal/builtinfunc/builtinfunc_test.go

@@ -0,0 +1,80 @@
+package builtinfunc
+
+import (
+	"fmt"
+	"slices"
+	"strings"
+	"testing"
+
+	"github.com/larvit/fejkdata/internal/grammar"
+)
+
+// TestRegistryShapes pins the builtin contract Prep relies on: every entry supplies prep,
+// and args parsed at compile only behind a check.
+func TestRegistryShapes(t *testing.T) {
+	for name, b := range builtins {
+		if b.prep == nil {
+			t.Errorf("builtin %q has no prep: Prep would call a nil func", name)
+		}
+		if b.arity != 0 && b.checkArgs == nil {
+			t.Errorf("builtin %q parses args in prep with no check", name)
+		}
+	}
+}
+
+func TestNoRefOperandsMatchesTheOperandGrammar(t *testing.T) {
+	for name, b := range builtins {
+		if b.operands == nil {
+			continue
+		}
+		if takesRef := slices.ContainsFunc(b.operands([]string{"/x"}), grammar.IsRef); b.noRefOperands == takesRef {
+			t.Errorf("%s: noRefOperands = %v, but its operands func reads a reference: %v", name, b.noRefOperands, takesRef)
+		}
+	}
+}
+
+func TestCheckNamesWhatACallGetsWrong(t *testing.T) {
+	for _, c := range []struct {
+		name string
+		args []string
+		want string
+	}{
+		{"nope", nil, `unknown function "nope"`},
+		{"luhn", []string{"1"}, "luhn takes 0 arguments, got 1"},
+		{"hex", nil, "hex takes 1 argument, got 0"},
+		{"calc", []string{"a +"}, `calc("a +"): `},
+		{"calc", []string{"a", "-1"}, "calc decimals "},
+		{"calc", nil, "calc takes an expression and an optional decimals count, got 0 args"},
+	} {
+		if err := Check(c.name, c.args); err == nil || !strings.HasPrefix(err.Error(), c.want) {
+			t.Errorf("Check(%s, %q) = %v, want it to start %q", c.name, c.args, err, c.want)
+		}
+	}
+	if err := Check("calc", []string{"a / b", "2"}); err != nil {
+		t.Errorf("Check(calc) = %v, want an expression over any operand accepted", err)
+	}
+}
+
+// TestArgGuardsPanic pins the guards that report a builtin arg its check should have
+// rejected. No data reaches them, since Check runs before Prep, so they are called directly.
+func TestArgGuardsPanic(t *testing.T) {
+	for name, call := range map[string]func(){
+		"atoi on an unvalidated arg":             func() { atoi("nope") },
+		"atof on an unvalidated arg":             func() { atof("nope") },
+		"prep on an expression that won't parse": func() { calcPrep([]string{"1 +"}) },
+	} {
+		mustPanic(t, name, call)
+	}
+}
+
+// mustPanic fails unless call panics with internalError's phrase, which is what
+// separates a reported invariant break from a silently wrong value.
+func mustPanic(t *testing.T, name string, call func()) {
+	t.Helper()
+	defer func() {
+		if r := recover(); r == nil || !strings.HasPrefix(fmt.Sprint(r), "fejkdata: internal error: ") {
+			t.Errorf("%s: recovered %v, want the invariant reported as an internal error", name, r)
+		}
+	}()
+	call()
+}

internal/datafiles/datafiles_test.go

@@ -0,0 +1,143 @@
+package datafiles
+
+import (
+	"errors"
+	"path/filepath"
+	"reflect"
+	"strings"
+	"testing"
+	"testing/fstest"
+)
+
+type handed struct {
+	dir  []string
+	name string
+	json any
+}
+
+func walk(t *testing.T, src Source) ([]handed, error) {
+	t.Helper()
+	var got []handed
+	err := src.Walk(func(c Category) error {
+		got = append(got, handed{c.Dir, c.Name, c.JSON})
+		return nil
+	})
+	return got, err
+}
+
+func TestWalkHandsEachCategoryInOrder(t *testing.T) {
+	got, err := walk(t, Source{FS: fstest.MapFS{
+		"a.json":          {Data: []byte(`{"x":"1"}`)},
+		"sub/b.json":      {Data: []byte(`"y"`)},
+		"sub/notes.txt":   {Data: []byte("not data")},
+		"empty/x.txt":     {Data: []byte("not data")},
+		".git/c.json":     {Data: []byte(`"hidden"`)},
+		"sub/.d.json":     {Data: []byte(`"hidden"`)},
+		"sub/deep/e.json": {Data: []byte(`"z"`)},
+	}})
+	if err != nil {
+		t.Fatal(err)
+	}
+	want := []handed{
+		{nil, "a", map[string]any{"x": "1"}},
+		{[]string{"sub"}, "b", "y"},
+		{[]string{"sub", "deep"}, "e", "z"},
+	}
+	if !reflect.DeepEqual(got, want) {
+		t.Errorf("Walk handed %#v, want %#v", got, want)
+	}
+}
+
+func TestWalkStartsAtTheBaseDir(t *testing.T) {
+	got, err := walk(t, Source{FS: fstest.MapFS{"data/a.json": {Data: []byte(`"x"`)}, "b.json": {Data: []byte(`"y"`)}}, BaseDir: "data"})
+	if err != nil || len(got) != 1 || got[0].name != "a" || got[0].dir != nil {
+		t.Errorf("Walk = %#v, %v, want a alone at the base", got, err)
+	}
+}
+
+func TestReadRowsReadsOnlyAFileBesideTheCategory(t *testing.T) {
+	src := Source{FS: fstest.MapFS{
+		"t.json":     {Data: []byte(`{"rows":"t.tsv"}`)},
+		"t.tsv":      {Data: []byte("key\nA\n")},
+		"sub/u.tsv":  {Data: []byte("key\nB\n")},
+		"sub/u.json": {Data: []byte(`{"rows":"u.tsv"}`)},
+	}, Label: "lbl"}
+	rows := map[string]string{}
+	err := src.Walk(func(c Category) error {
+		data, err := c.ReadRows(c.Name + ".tsv")
+		rows[c.Name] = data
+		if err != nil {
+			return err
+		}
+		if _, err := c.ReadRows("x.tsv"); err == nil || err.Error() != "rows names x.tsv, which is not beside it in "+map[string]string{"t": "lbl", "u": "lbl/sub"}[c.Name] {
+			t.Errorf("ReadRows(x.tsv) = %v, want the file named missing beside %s", err, c.Name)
+		}
+		return nil
+	})
+	if err != nil || rows["t"] != "key\nA\n" || rows["u"] != "key\nB\n" {
+		t.Errorf("Walk = %v, read %q", err, rows)
+	}
+}
+
+func TestWalkRefusesARowsFileNoCategoryNames(t *testing.T) {
+	_, err := walk(t, Source{FS: fstest.MapFS{"a.json": {Data: []byte(`"x"`)}, "a.tsv": {Data: []byte("key\n")}}, Label: "lbl"})
+	if err == nil || !strings.HasPrefix(err.Error(), "lbl/a.tsv: no category names it in its rows") {
+		t.Errorf("Walk = %v, want a.tsv refused as named by no category", err)
+	}
+}
+
+func TestWalkLabelsWhatACategoryFileGetsWrong(t *testing.T) {
+	for _, c := range []struct {
+		name string
+		fs   fstest.MapFS
+		want string
+	}{
+		{"its compile", fstest.MapFS{"a.json": {Data: []byte(`"x"`)}}, "lbl/a.json: bad"},
+		{"its JSON", fstest.MapFS{"a.json": {Data: []byte(`{`)}}, "lbl/a.json: unexpected end of JSON input"},
+		{"its name", fstest.MapFS{"a b.json": {Data: []byte(`"x"`)}}, "lbl/a b.json: category "},
+		{"its folder's name", fstest.MapFS{"a b/c.json": {Data: []byte(`"x"`)}}, "lbl/a b: folder "},
+	} {
+		err := Source{FS: c.fs, Label: "lbl"}.Walk(func(Category) error { return errors.New("bad") })
+		if err == nil || !strings.HasPrefix(err.Error(), c.want) {
+			t.Errorf("%s: Walk = %v, want it to start %q", c.name, err, c.want)
+		}
+	}
+}
+
+func TestWalkChecksAFolderNameOnlyWhenItHoldsData(t *testing.T) {
+	if _, err := walk(t, Source{FS: fstest.MapFS{"a b/notes.txt": {Data: []byte("x")}, "c.json": {Data: []byte(`"x"`)}}}); err != nil {
+		t.Errorf("Walk = %v, want a folder holding no data skipped whatever its name", err)
+	}
+}
+
+func TestWalkRefusesADiskPathThatIsNoDirectory(t *testing.T) {
+	dir := t.TempDir()
+	for _, c := range []struct{ path, want string }{
+		{"", "a data path is empty"},
+		{filepath.Join(dir, "none"), "data path " + filepath.Join(dir, "none") + ": "},
+	} {
+		_, err := walk(t, Source{FS: fstest.MapFS{}, Label: c.path, OnDisk: true})
+		if err == nil || !strings.HasPrefix(err.Error(), c.want) {
+			t.Errorf("Walk(%q) = %v, want it to start %q", c.path, err, c.want)
+		}
+	}
+}
+
+func TestLoadHandsOneCategoryAndItsRows(t *testing.T) {
+	src := Source{FS: fstest.MapFS{
+		"data/sub/t.json": {Data: []byte(`{"rows":"t.tsv"}`)},
+		"data/sub/t.tsv":  {Data: []byte("key\nA\n")},
+		"data/sub/u.json": {Data: []byte(`{`)},
+	}, BaseDir: "data"}
+	var got handed
+	var rows string
+	err := src.Load([]string{"sub"}, "t", func(c Category) error {
+		got = handed{c.Dir, c.Name, c.JSON}
+		var err error
+		rows, err = c.ReadRows("t.tsv")
+		return err
+	})
+	if err != nil || got.name != "t" || !reflect.DeepEqual(got.dir, []string{"sub"}) || rows != "key\nA\n" {
+		t.Errorf("Load = %v, handed %#v with rows %q", err, got, rows)
+	}
+}

internal/datatype/datatype_test.go

@@ -0,0 +1,25 @@
+package datatype
+
+import "testing"
+
+func TestEachDatatypeIsSpelledAsDataWritesIt(t *testing.T) {
+	for d, want := range map[DataType][2]string{
+		String:  {"string", "text"},
+		Integer: {"integer", "an integer"},
+		Number:  {"number", "a number"},
+		Boolean: {"boolean", "a boolean"},
+	} {
+		if d.String() != want[0] || Noun(d) != want[1] {
+			t.Errorf("%d: String = %q, Noun = %q, want %q", int(d), d.String(), Noun(d), want)
+		}
+	}
+	if Count != 4 {
+		t.Errorf("Count = %d, want the four datatypes", Count)
+	}
+}
+
+func TestStringNamesADatatypeNoDataWrites(t *testing.T) {
+	if got := DataType(9).String(); got != "DataType(9)" {
+		t.Errorf("String = %q, want DataType(9)", got)
+	}
+}

internal/proven/proven_test.go

@@ -0,0 +1,88 @@
+package proven
+
+import (
+	"math"
+	"testing"
+
+	"github.com/larvit/fejkdata/internal/datatype"
+	"github.com/larvit/fejkdata/internal/grammar"
+)
+
+func TestLiteralSaysWhichDatatypesItsTextIs(t *testing.T) {
+	for _, c := range []struct {
+		text string
+		not  [datatype.Count]bool
+	}{
+		{"42", [datatype.Count]bool{datatype.Boolean: true}},
+		{"1.5", [datatype.Count]bool{datatype.Integer: true, datatype.Boolean: true}},
+		{"true", [datatype.Count]bool{datatype.Integer: true, datatype.Number: true}},
+		{"007", [datatype.Count]bool{datatype.Integer: true, datatype.Number: true, datatype.Boolean: true}},
+		{"-0", [datatype.Count]bool{datatype.Integer: true, datatype.Number: true, datatype.Boolean: true}},
+	} {
+		v := Literal(c.text)
+		for d := datatype.Integer; d <= datatype.Boolean; d++ {
+			if (v.Not[d] != "") != c.not[d] {
+				t.Errorf("Literal(%q).Not[%s] = %q", c.text, d, v.Not[d])
+			}
+		}
+	}
+	if v := Literal("-0"); v.Not[datatype.Integer] != `"-0" is zero written with a sign; write "0"` {
+		t.Errorf("Literal(-0) = %q, want the unsigned spelling named", v.Not[datatype.Integer])
+	}
+}
+
+func TestOrKeepsTheBoundsOfBothAndTheFirstReason(t *testing.T) {
+	v := Bounded(1, 2, true).Or(Bounded(-3, 0.5, false))
+	if v.Lo != -3 || v.Hi != 2 || v.Integral || v.NonZero != 0 {
+		t.Errorf("Or = %+v, want [-3, 2], not integral, possibly zero", v)
+	}
+	if v := Unproven("first").Or(Unproven("second")); v.NotOperand != "first" || v.Not[datatype.Number] != "first" {
+		t.Errorf("Or = %+v, want the first reason kept", v)
+	}
+}
+
+func TestCalcBoundsAnExpressionFromItsOperands(t *testing.T) {
+	operand := func(name string) Value {
+		return map[string]Value{"a": Bounded(1, 9, true), "b": Bounded(0, 9, true), "big": Bounded(0, 1e299, true), "word": Unproven("it is text")}[name]
+	}
+	for expr, want := range map[string]string{
+		"a * 2 + 1": "",
+		"a / b":     "divides by b, which is not proven nonzero",
+		"big * 100": "(big * 100) is not proven within 1e300",
+		"big":       "",
+		"word + 1":  `operand "word": it is text`,
+		"-(a - 10)": "",
+	} {
+		c, err := grammar.ParseCalc(expr)
+		if err != nil {
+			t.Fatal(err)
+		}
+		v, doubt := Calc(c.Expr, operand)
+		if doubt != want {
+			t.Errorf("Calc(%s) doubts %q, want %q", expr, doubt, want)
+		}
+		if expr == "a * 2 + 1" && (v.Lo != 3 || v.Hi != 19 || !v.Integral || v.NonZero != 3) {
+			t.Errorf("Calc(%s) = %+v, want [3, 19], integral, nonzero by 3", expr, v)
+		}
+		if expr == "-(a - 10)" && (v.Lo != 1 || v.Hi != 9) {
+			t.Errorf("Calc(%s) = %+v, want [1, 9]", expr, v)
+		}
+	}
+	lone, _ := grammar.ParseCalc("x")
+	if _, doubt := Calc(lone.Expr, func(string) Value { return Bounded(0, 1e301, true) }); doubt != "x is not proven within 1e300" {
+		t.Errorf("Calc(x) doubts %q, want a lone operand held to the limit", doubt)
+	}
+}
+
+func TestPrintedNumberWidensItsBoundsByTheRounding(t *testing.T) {
+	v := PrintedNumber("float(0,1,1)", Bounded(0.2, 0.8, false), 1)
+	if math.Abs(v.Lo-0.15) > 1e-12 || math.Abs(v.Hi-0.85) > 1e-12 || v.Not[datatype.Integer] == "" || v.Not[datatype.Number] != "" {
+		t.Errorf("PrintedNumber = %+v, want [0.15, 0.85], a number and no integer", v)
+	}
+	if v := PrintedNumber("calc(a)", Bounded(1, 2, true), ShortestDecimals); v.Not[datatype.Integer] != "" {
+		t.Errorf("PrintedNumber = %+v, want a whole value printed as an integer", v)
+	}
+	if v := Printing("digits(3)", datatype.String, Bounded(0, 999, true)); v.Not[datatype.Integer] != "{digits(3)} prints text, not an integer" {
+		t.Errorf("Printing = %q, want the text named", v.Not[datatype.Integer])
+	}
+}