cmd/fejkdata/lone_test.go

@@ -0,0 +1,47 @@
+package main
+
+import (
+	"testing"
+
+	"github.com/larvit/fejkdata/internal/grammar"
+)
+
+// grammarLoneReference is the path a format reads when the grammar parses it as one path
+// read of one reference from the root, and nothing else.
+func grammarLoneReference(text string) (string, bool) {
+	toks, err := grammar.ParseFormat(text)
+	if err != nil || len(toks) != 1 || toks[0].Kind != grammar.PathRead || len(toks[0].Arms) != 1 {
+		return "", false
+	}
+	sigil, path, err := grammar.RefShape(toks[0].Arms[0])
+	if err != nil || sigil != "/" {
+		return "", false
+	}
+	return path, true
+}
+
+func TestLoneReferenceAgreesWithTheGrammar(t *testing.T) {
+	for _, text := range []string{
+		"{/sv_SE.person}",
+		"{/misc.currency[US Dollar (Next day)]}",
+		"{/t[a as b].c}",
+		"{/t[f(x)]}",
+		"{/a}{/b}",
+		"{/x}}",
+		"{/}",
+		"{/.x}",
+		" {/x}",
+		"{/a|/b}",
+		"{/x as p}",
+		"{//x}",
+		"{/x(1)}",
+		"{.x}",
+		"x",
+	} {
+		path, lone := loneReference(text)
+		want, wantLone := grammarLoneReference(text)
+		if lone != wantLone || path != want {
+			t.Errorf("loneReference(%q) = %q, %v; the grammar reads %q, %v", text, path, lone, want, wantLone)
+		}
+	}
+}

cmd/fejkdata/main_test.go

@@ -249,6 +249,7 @@ func TestRunTakesNoOperand(t *testing.T) {
 		want string
 	}{
 		{[]string{"sv_SE.person"}, "echo '{/sv_SE.person}' | fejkdata"},
+		{[]string{"/en_US.address"}, "echo '{/en_US.address}' | fejkdata"},
 		{[]string{"{/en_US.person}"}, "echo '{/en_US.person}' | fejkdata"},
 		{[]string{"name: {/sv_SE.person.last}"}, "echo 'name: {/sv_SE.person.last}' | fejkdata"},
 		{[]string{"geo.US.locality[O'Fallon].name"}, `echo '{/geo.US.locality[O'\''Fallon].name}' | fejkdata`},
@@ -494,6 +495,8 @@ func TestRunTemplateMisuse(t *testing.T) {
 		"42":                    "number",
 		"42\n":                  "number",
 		"true\n":                "boolean",
+		"null\n":                "only null",
+		" null ":                "only null",
 		"{//sv_SE.person}":      "write {/sv_SE.person}",
 	} {
 		code, out, errb := runOut(stdin, "--seed", "1")

datatype_test.go

@@ -48,17 +48,16 @@ func TestDatatypeRejectsAValueItsTypeRejects(t *testing.T) {
 		{"a weighted item beside a typed one", `[{"format":"1","datatype":"integer"},{"format":"2","weight":3}]`, `give it "datatype": "integer"`},
 		{"an item beside a typed column it reads", `["{/src.score}","5"]`, `write it as {"format":"5","datatype":"integer"}`},
 		{"a typed item beside a string column it reads", `["{/src.code}",{"format":"1","datatype":"integer"}]`, `write it as {"format":"{/src.code}","datatype":"integer"}`},
-		{"text beside a typed column it reads", `["{/src.score}","n/a"]`, `to read that column as text, write {"format":"{text}","text":"{/src.score}"}`},
+		{"text beside a typed column it reads", `["{/src.score}","n/a"]`, `to read that column as text, write "{/src.score}" as {"format":"{/src.score}","datatype":"string"}`},
-		{"a datatype over a typed column", `{"format":"{/src.score}","datatype":"integer"}`, `{/src.score} takes datatype integer from the column it reads; drop "datatype"`},
 		{"a datatype a typed column's values reject", `{"format":"{/src.score}","datatype":"boolean"}`, "{int(1,9)} prints an integer, not a boolean"},
-		{"two typed columns it reads", `["{/src.score}","{/src.flag}"]`, `so to read "{/src.score}" as text, write {"format":"{text}","text":"{/src.score}"}`},
+		{"two typed columns it reads", `["{/src.score}","{/src.flag}"]`, `so to read "{/src.score}" as text, write "{/src.score}" as {"format":"{/src.score}","datatype":"string"}`},
 		{"a typed column read that holds the datatype declared beside it", `[{"format":"1.5","datatype":"number"},"{/src.score}"]`, `so write "{/src.score}" as {"format":"{/src.score}","datatype":"number"}`},
 		{"a typed column read holding the datatype of another", `["{/src.ratio}","{/src.score}"]`, `so write "{/src.ratio}" as {"format":"{/src.ratio}","datatype":"integer"}`},
-		{"text before a typed column it reads", `["n/a","{/src.score}"]`, `to read that column as text, write {"format":"{text}","text":"{/src.score}"}`},
+		{"text before a typed column it reads", `["n/a","{/src.score}"]`, `to read that column as text, write "{/src.score}" as {"format":"{/src.score}","datatype":"string"}`},
 		{"a weighted item beside a typed column it reads", `["{/src.score}",{"format":"5","weight":2}]`, `give it "datatype": "integer"`},
 		{"a typed column read before the datatype it holds", `["{/src.score}",{"format":"1.5","datatype":"number"}]`, `so write "{/src.score}" as {"format":"{/src.score}","datatype":"number"}`},
-		{"a typed column read beside a datatype it does not hold", `["{/src.score}",{"format":"true","datatype":"boolean"}]`, `so to read "{/src.score}" as text, write {"format":"{text}","text":"{/src.score}"}`},
+		{"a typed column read beside a datatype it does not hold", `["{/src.score}",{"format":"true","datatype":"boolean"}]`, `so to read "{/src.score}" as text, write "{/src.score}" as {"format":"{/src.score}","datatype":"string"}`},
-		{"text beside a weighted typed column read", `[{"format":"{/src.score}","weight":3},"n/a"]`, `to read that column as text, set its "format" to "{text}" and add "text": "{/src.score}"`},
+		{"text beside a weighted typed column read", `[{"format":"{/src.score}","weight":3},"n/a"]`, `to read that column as text, give "{/src.score}" "datatype": "string"`},
 		{"a value of the column it reads", `{"format":"{/src.code}","datatype":"integer"}`, `"2x" is not an integer`},
 		{"a null read into text", `{"format":"{x}","x":"{/src.score}","datatype":"integer"}`, "reads a null"},
 		{"a sample with leading zeros", `{"format":"{digits(3)}","datatype":"integer"}`, "{digits(3)} prints text, not an integer"},
@@ -233,3 +232,27 @@ func TestASignedZeroIsZero(t *testing.T) {
 		t.Errorf("columns = %+v, want each written as its format", c)
 	}
 }
+
+func TestADeclaredDatatypeOverAColumnRead(t *testing.T) {
+	f := newGenerator(t, writeData(t, map[string]string{
+		"src": `{"format":"","score":[null,{"format":"{int(1,9)}","datatype":"integer"}]}`,
+		"row": `{"format":"","same":{"format":"{/src.score}","datatype":"integer"},"text":{"format":"{/src.score}","datatype":"string"}}`,
+	}), WithSeed(1))
+	empty := 0
+	for i := 0; i < 50; i++ {
+		r, err := f.FakeRecord("row")
+		if err != nil {
+			t.Fatal(err)
+		}
+		same, text := r.Columns()[0], r.Columns()[1]
+		if same.DataType != DataTypeInteger || text.DataType != DataTypeString || text.Null {
+			t.Fatalf("columns = %+v, want an integer column restated and a string column never null", r.Columns())
+		}
+		if text.Value == "" {
+			empty++
+		}
+	}
+	if empty == 0 {
+		t.Error(`50 records never read a null as "", want the string column to render one so`)
+	}
+}

imports_test.go

@@ -40,6 +40,9 @@ func TestPackageImports(t *testing.T) {
 		"internal/proven":      {"internal/datatype", "internal/grammar", "internal/invariant"},
 		"internal/rows":        {"internal/drawstate", "internal/grammar", "internal/invariant"},
 	}
+	testsAlso := map[string][]string{
+		"cmd/fejkdata": {"internal/grammar"},
+	}
 	seen := map[string]bool{}
 	eachPackage(t, func(dir string, pkg *build.Package) {
 		seen[dir] = true
@@ -49,6 +52,10 @@ func TestPackageImports(t *testing.T) {
 			return
 		}
 		for _, imp := range slices.Concat(pkg.Imports, pkg.TestImports, pkg.XTestImports) {
+			may := may
+			if !slices.Contains(pkg.Imports, imp) {
+				may = slices.Concat(may, testsAlso[dir])
+			}
 			if imp != module && !strings.HasPrefix(imp, module+"/") {
 				continue
 			}

inline_test.go

@@ -175,22 +175,22 @@ func TestIsTemplate(t *testing.T) {
 		"{//sv_SE.person}":                       true,
 		"{/misc.currency[US Dollar (Next day)]}": true,
 		"/sv_SE.person":                          false,
-		"//sv_SE.person":                         false,
 	} {
 		if got, err := IsTemplate(arg); err != nil || got != want {
 			t.Errorf("IsTemplate(%q) = %v, %v; want %v", arg, got, err, want)
 		}
 	}
 	for arg, want := range map[string]string{
-		"[abc]":       `starts with "["`,
+		"[abc]":          `starts with "["`,
-		"[abc].field": `starts with "["`,
+		"[abc].field":    `starts with "["`,
-		"x[1]y":       `"]"`,
+		"x[1]y":          `"]"`,
-		"x[[1]]":      `"["`,
+		"x[[1]]":         `"["`,
-		"x[]":         "empty",
+		"x[]":            "empty",
-		"a]b":         `holds a "]"`,
+		"//sv_SE.person": "write /sv_SE.person",
-		"a}b":         `holds a "}"`,
+		"a]b":            `holds a "]"`,
-		`"abc`:        `holds a "\""`,
+		"a}b":            `holds a "}"`,
-		`"a]b`:        `holds a "\""`, // the opener the reader typed, not the bracket behind it
+		`"abc`:           `holds a "\""`,
+		`"a]b`:           `holds a "\""`, // the opener the reader typed, not the bracket behind it
 	} {
 		if _, err := IsTemplate(arg); err == nil || !strings.Contains(err.Error(), want) {
 			t.Errorf("IsTemplate(%q) = %v; want it rejected naming %s", arg, err, want)

loading_test.go

@@ -302,27 +302,6 @@ func TestNewErrors(t *testing.T) {
 			map[string]string{"a": `{"format":"{x}","x":"1","-":"2"}`},
 			`field "-" is reserved`,
 		},
-		// A repeated arm skews an alternation, which weight is the spelling for.
-		"repeated alternation arm": {
-			map[string]string{"a": `{"format":"{x|x}","x":"1"}`},
-			`arm "x" is repeated`,
-		},
-		"repeated arm among others": {
-			map[string]string{"a": `{"format":"{x|y|x}","x":"1","y":"2"}`},
-			`arm "x" is repeated`,
-		},
-		"repeated path arm": {
-			map[string]string{"a": `{"format":"{p.v|p.v}","p":{"format":"{v}","v":"1"}}`},
-			`arm "p.v" is repeated`,
-		},
-		// A reference arm is the only kind that reaches the repeat check by passing
-		// the per-arm checks rather than falling through them.
-		"repeated reference arm": {
-			map[string]string{"a": `"x"`, "b": `"{/a|/a}"`},
-			`arm "/a" is repeated`,
-		},
-		// An arm that is broken on its own terms is reported as that, not as a
-		// repeat: the repeat is a consequence of the real mistake.
 		"repeated arm with no path": {
 			map[string]string{"a": `"{/|/}"`},
 			"reference has no path",
@@ -361,9 +340,10 @@ func TestNewErrors(t *testing.T) {
 		"folder named Repeat":        {map[string]string{"Repeat/cat": `"1"`}, "Repeat.cat", "1"},
 		"field with a closing paren": {map[string]string{"a": `{"format":"{b)c}","b)c":"2"}`}, "a", "2"},
 		"repeat without a separator": {map[string]string{"a": `{"format":"{x}","repeat":3,"x":"1"}`}, "a", "111"},
-		// One name in two separate tokens is two independent draws, not a repeated
+		"one name in two tokens":     {map[string]string{"a": `{"format":"{x}{x}","x":"1"}`}, "a", "11"},
-		// arm; only a repeat within one alternation is rejected.
+		"repeated alternation arm":   {map[string]string{"a": `{"format":"{x|x}","x":"1"}`}, "a", "1"},
-		"one name in two tokens": {map[string]string{"a": `{"format":"{x}{x}","x":"1"}`}, "a", "11"},
+		"repeated path arm":          {map[string]string{"a": `{"format":"{p.v|p.v}","p":{"format":"{v}","v":"1"}}`}, "a", "1"},
+		"repeated reference arm":     {map[string]string{"a": `"x"`, "b": `"{/a|/a}"`}, "b", "x"},
 	}
 	for name, c := range accepted {
 		f, err := New(WithoutShippedData(), WithDataPath(writeData(t, c.files)))

name_test.go

@@ -186,8 +186,6 @@ func TestNameErrors(t *testing.T) {
 			`"format" is an option and can never be a name`},
 		{"no reference or field", map[string]string{"card": `{"format":"{word as w}{w}{w}","words":["a","b"]}`},
 			`no field "word"; a binding names a field, or a reference`},
-		{"read once through a field", map[string]string{"card": `{"format":"{place as p}{p.x}","place":{"format":"{x}","x":["a","b"]}}`},
-			""},
 		{"read once through a path that does not resolve", map[string]string{"word": `{"format":"{w}","w":["a","b"]}`, "card": `"{/word as a}{a.zz}"`},
 			`no field "zz"`},
 		{"read once through a field path that does not resolve", map[string]string{"card": `{"format":"{place as p}{p.zz}","place":{"format":"{x}","x":["a","b"]}}`},
@@ -198,22 +196,10 @@ func TestNameErrors(t *testing.T) {
 			""},
 		{"a misspelt name", map[string]string{"word": `["a","b"]`, "card": `"{/word as p}{p}{p}{pp}"`},
 			`no field or name "pp"; the names bound here are "p"`},
-		{"read once through a path", map[string]string{"word": `{"format":"{w}","w":["a","b"]}`, "card": `"{/word as a}{a.w} {/word.w}"`},
-			""},
-		{"read once whole, bound to a reference path", map[string]string{"word": `{"format":"{w}","w":["a","b"]}`, "card": `"{/word.w as c}{c} {/word.w}"`},
-			""},
-		{"read once through a step up", map[string]string{"region.json": nameTables()["region.json"], "region.tsv": nameTables()["region.tsv"], "municipality.json": nameTables()["municipality.json"], "municipality.tsv": nameTables()["municipality.tsv"], "card": `"{/municipality as m}{m..region.name}"`},
-			""},
-		{"read once as a calc operand", map[string]string{"word": `["1","2"]`, "card": `"{/word as w}{calc(w * 2)}"`},
-			""},
 		{"read outside a repeat in the root choice", map[string]string{"word": `["a","b"]`, "card": `[{"format":"{/word as p}{p}{p}","repeat":2},"{p}"]`},
 			`name "p" is bound at an item of the root choice, inside a repeat`},
 		{"an empty name", map[string]string{"word": `["a","b"]`, "card": `"{/word as }"`},
 			"a binding names nothing"},
-		{"read once whole", map[string]string{"word": `["a","b"]`, "card": `{"format":"{/word as w}{x}","x":"{w}"}`},
-			""},
-		{"read once whole, as a transform's operand", map[string]string{"word": `["a","b"]`, "card": `"{/word as w}{uppercase(w)}"`},
-			""},
 		{"rendered twice where a path reads it", map[string]string{"word": `{"format":"{w}-{w}","w":["a","b"]}`, "card": `"{/word as n}{n}|{n.w}"`},
 			`{n} renders field "w" twice`},
 		{"a binding in a cell", map[string]string{"word": `["a","b"]`, "t.json": `{"format":"{k}","rows":"t.tsv","key":"k"}`, "t.tsv": "k\tc\nx\t{/word as w}{w}{w}\ny\tz\n"},
@@ -258,6 +244,28 @@ func TestNameErrors(t *testing.T) {
 	}
 }
 
+func TestANameReadOnceLoads(t *testing.T) {
+	for name, files := range map[string]map[string]string{
+		"through a path":                   {"word": `{"format":"{w}","w":["a","b"]}`, "card": `"{/word as a}{a.w} {/word.w}"`},
+		"whole, bound to a reference path": {"word": `{"format":"{w}","w":["a","b"]}`, "card": `"{/word.w as c}{c} {/word.w}"`},
+		"through a step up":                {"region.json": nameTables()["region.json"], "region.tsv": nameTables()["region.tsv"], "municipality.json": nameTables()["municipality.json"], "municipality.tsv": nameTables()["municipality.tsv"], "card": `"{/municipality as m}{m..region.name}"`},
+		"as a calc operand":                {"word": `["1","2"]`, "card": `"{/word as w}{calc(w * 2)}"`},
+		"whole":                            {"word": `["a","b"]`, "card": `{"format":"{/word as w}{x}","x":"{w}"}`},
+		"whole, as a transform's operand":  {"word": `["a","b"]`, "card": `"{/word as w}{uppercase(w)}"`},
+	} {
+		withJSON := map[string]string{}
+		for file, body := range files {
+			if !strings.Contains(file, ".") {
+				file += ".json"
+			}
+			withJSON[file] = body
+		}
+		if _, err := New(WithoutShippedData(), WithDataPath(writeFiles(t, withJSON))); err != nil {
+			t.Errorf("%s: New() = %v, want it to load", name, err)
+		}
+	}
+}
+
 func TestANameBindsAReferenceFromItsFolder(t *testing.T) {
 	dir := writeData(t, map[string]string{
 		"sv/word": `["a","b","c","d","e","f","g","h"]`,

node_test.go

@@ -59,7 +59,6 @@ func TestNodeCompileErrors(t *testing.T) {
 		`[1, 2]`,                           // a choice of numbers
 		`5`,                                // unsupported node type
 		`[]`,                               // empty choice
-		`["a","a"]`,                        // a repeated item is a weight
 		`[{"format":"A","weight":-1},"B"]`, // negative weight
 		`[{"format":"A","weight":0},{"format":"B","weight":0}]`,         // weights sum to zero
 		`[{"format":"A","weight":1e308},{"format":"B","weight":1e308}]`, // weights overflow to +Inf

path_test.go

@@ -187,10 +187,11 @@ func TestFakePathNavigation(t *testing.T) {
 
 func TestALeadingSlashIsThePath(t *testing.T) {
 	f := newGenerator(t, writeData(t, map[string]string{"person": `{"format":"{first}","first":"Ada"}`}), WithSeed(1))
-	for _, path := range []string{"/person", "//person.first"} {
+	if v := fake(t, f, "/person"); v != "Ada" {
-		if v := fake(t, f, path); v != "Ada" {
+		t.Errorf("Fake(/person) = %q, want Ada", v)
-			t.Errorf("Fake(%s) = %q, want Ada", path, v)
+	}
-		}
+	if _, err := f.Fake("//person"); err == nil || !strings.Contains(err.Error(), "write /person") {
+		t.Errorf("Fake(//person) = %v, want it refused naming /person", err)
 	}
 	r, err := f.FakeRecord("/person")
 	if err != nil || len(r.Columns()) != 1 || r.Columns()[0].Value != "Ada" {

spellings_test.go

@@ -29,25 +29,29 @@ func TestOneItemChoiceIsItsItem(t *testing.T) {
 	if r, isTemplate := compiled(t, `[{"format":"","d":"x"}]`).(*template); !isTemplate || !r.isRecord {
 		t.Error("a one-item choice of a record is no record, want the record it holds")
 	}
+	if _, err := resolved(t, `[{"format":"a","weight":2}]`); err == nil || !strings.Contains(err.Error(), "no effect here") {
+		t.Errorf("a weight on a one-item choice's item = %v, want it refused as doing nothing", err)
+	}
 }
 
-func TestRepeatedChoiceItemIsRejected(t *testing.T) {
+func TestARepeatedItemCountsAsWritten(t *testing.T) {
-	for src, want := range map[string]string{
+	for _, src := range []string{`["a", "a", "b"]`, `[{"format":"{x}","x":"1"},{"format":"{x}","x":"1"}]`, `{"format":"{w}","w":["", "", "x"]}`, `{"format":"","w":[null,null,"a"]}`, `{"format":"{x|x|y}","x":"1","y":"2"}`} {
-		`["a", "a", "b"]`: `{ "format": "a", "weight": 2 }`,
+		if _, err := resolved(t, src); err != nil {
-		`[{"format":"{x}","x":"1"},{"format":"{x}","x":"1"}]`: "repeats item",
+			t.Errorf("compile(%s) = %v, want it loaded", src, err)
-		`{"format":"{w}","w":["", "", "x"]}`:                  `{ "format": "", "weight": 2 }`,
-		`{"format":"","w":[null,null,"a"]}`:                   "a null takes no weight",
-	} {
-		if _, err := resolved(t, src); err == nil || !strings.Contains(err.Error(), want) {
-			t.Errorf("compile(%s) = %v, want an error naming %s", src, err, want)
 		}
 	}
-	if _, err := resolved(t, `[{"format":"a","weight":2}, "b"]`); err != nil {
+	f, n, as := engine(1), compiled(t, `["a", "a", "b"]`), 0
-		t.Errorf("compile(weighted a, b) = %v", err)
+	for i := 0; i < 600; i++ {
+		if renderOnce(f.drawState, n) == "a" {
+			as++
+		}
+	}
+	if as < 340 || as > 460 {
+		t.Errorf(`["a","a","b"] drew a %d times in 600, want about 400`, as)
 	}
 }
 
-func TestInertObjectIsRejected(t *testing.T) {
+func TestASeparatorWithoutARepeatIsRejected(t *testing.T) {
 	for src, want := range map[string]string{
 		`{"format":"{x}","x":"v","separator":","}`: "separator",
 	} {

struct_test.go

@@ -269,6 +269,9 @@ func TestFakeStructErrors(t *testing.T) {
 		{&struct {
 			A int `fake:"{\"format\":\"{int(1,9)}\",\"datatype\":\"integer\"}"`
 		}{}, `its Go type int sets the datatype; drop "datatype"`},
+		{&struct {
+			A string `fake:"{\"format\":\"x\",\"datatype\":\"string\"}"`
+		}{}, `its Go type string sets the datatype; drop "datatype"`},
 		{&struct {
 			A int `fake:"[null,\"{int(1,9)}\"]"`
 		}{}, "can draw null, which int cannot hold; make it *int"},