empty: added empty and zero length detection (#109)

Fixes #108

Co-authored-by: Anton Telyshev <[email protected]>

README.md

@@ -227,11 +227,15 @@ assert.Less(t, len(arr), 0)
 assert.Greater(t, 0, len(arr))
 assert.Less(t, len(arr), 1)
 assert.Greater(t, 1, len(arr))
+assert.Zero(t, len(arr))
+assert.Empty(t, len(arr))
 
 assert.NotEqual(t, 0, len(arr))
 assert.NotEqualValues(t, 0, len(arr))
 assert.Less(t, 0, len(arr))
 assert.Greater(t, len(arr), 0)
+assert.NotZero(t, len(arr))
+assert.NotEmpty(t, len(arr))
 
 ✅
 assert.Empty(t, arr)

analyzer/testdata/src/checkers-default/empty/empty_test.go.golden

@@ -44,6 +44,10 @@ func TestEmptyChecker(t *testing.T) {
 		assert.Emptyf(t, elems, "msg with args %d %s", 42, "42") // want "empty: use assert\\.Emptyf"
 		assert.Empty(t, elems)                                   // want "empty: use assert\\.Empty"
 		assert.Emptyf(t, elems, "msg with args %d %s", 42, "42") // want "empty: use assert\\.Emptyf"
+		assert.Empty(t, elems)                                   // want "empty: use assert\\.Empty"
+		assert.Emptyf(t, elems, "msg with args %d %s", 42, "42") // want "empty: use assert\\.Emptyf"
+		assert.Empty(t, elems)                                   // want "empty: use assert\\.Empty"
+		assert.Emptyf(t, elems, "msg with args %d %s", 42, "42") // want "empty: use assert\\.Emptyf"
 
 		// Valid.
 		assert.Empty(t, elems)
@@ -65,6 +69,10 @@ func TestEmptyChecker(t *testing.T) {
 		assert.NotEmptyf(t, elems, "msg with args %d %s", 42, "42") // want "empty: use assert\\.NotEmptyf"
 		assert.NotEmpty(t, elems)                                   // want "empty: use assert\\.NotEmpty"
 		assert.NotEmptyf(t, elems, "msg with args %d %s", 42, "42") // want "empty: use assert\\.NotEmptyf"
+		assert.NotEmpty(t, elems)                                   // want "empty: use assert\\.NotEmpty"
+		assert.NotEmptyf(t, elems, "msg with args %d %s", 42, "42") // want "empty: use assert\\.NotEmptyf"
+		assert.NotEmpty(t, elems)                                   // want "empty: use assert\\.NotEmpty"
+		assert.NotEmptyf(t, elems, "msg with args %d %s", 42, "42") // want "empty: use assert\\.NotEmptyf"
 
 		// Valid.
 		assert.NotEmpty(t, elems)

internal/checkers/empty.go

@@ -21,11 +21,15 @@ import (
 //	assert.Greater(t, 0, len(arr))
 //	assert.Less(t, len(arr), 1)
 //	assert.Greater(t, 1, len(arr))
+//	assert.Zero(t, len(arr))
+//	assert.Empty(t, len(arr))
 //
 //	assert.NotEqual(t, 0, len(arr))
 //	assert.NotEqualValues(t, 0, len(arr))
 //	assert.Less(t, 0, len(arr))
 //	assert.Greater(t, len(arr), 0)
+//	assert.NotZero(t, len(arr))
+//	assert.NotEmpty(t, len(arr))
 //
 // and requires
 //
@@ -56,10 +60,23 @@ func (checker Empty) checkEmpty(pass *analysis.Pass, call *CallMeta) *analysis.D
 		)
 	}
 
+	if len(call.Args) == 0 {
+		return nil
+	}
+
+	a := call.Args[0]
+	switch call.Fn.NameFTrimmed {
+	case "Zero", "Empty":
+		lenArg, ok := isBuiltinLenCall(pass, a)
+		if ok {
+			return newUseEmptyDiagnostic(a.Pos(), a.End(), lenArg)
+		}
+	}
+
 	if len(call.Args) < 2 {
 		return nil
 	}
-	a, b := call.Args[0], call.Args[1]
+	b := call.Args[1]
 
 	switch call.Fn.NameFTrimmed {
 	case "Len":
@@ -110,10 +127,23 @@ func (checker Empty) checkNotEmpty(pass *analysis.Pass, call *CallMeta) *analysi
 		)
 	}
 
+	if len(call.Args) == 0 {
+		return nil
+	}
+
+	a := call.Args[0]
+	switch call.Fn.NameFTrimmed {
+	case "NotZero", "NotEmpty":
+		lenArg, ok := isBuiltinLenCall(pass, a)
+		if ok {
+			return newUseNotEmptyDiagnostic(a.Pos(), a.End(), lenArg)
+		}
+	}
+
 	if len(call.Args) < 2 {
 		return nil
 	}
-	a, b := call.Args[0], call.Args[1]
+	b := call.Args[1]
 
 	switch call.Fn.NameFTrimmed {
 	case "NotEqual", "NotEqualValues":

internal/testgen/gen_empty.go

@@ -59,6 +59,8 @@ func (g EmptyTestsGenerator) TemplateData() any {
 					{Fn: "GreaterOrEqual", Argsf: "0, len(elems)", ReportMsgf: report, ProposedFn: "Empty", ProposedArgsf: "elems"},
 					{Fn: "Less", Argsf: "len(elems), 1", ReportMsgf: report, ProposedFn: "Empty", ProposedArgsf: "elems"},
 					{Fn: "Greater", Argsf: "1, len(elems)", ReportMsgf: report, ProposedFn: "Empty", ProposedArgsf: "elems"},
+					{Fn: "Zero", Argsf: "len(elems)", ReportMsgf: report, ProposedFn: "Empty", ProposedArgsf: "elems"},
+					{Fn: "Empty", Argsf: "len(elems)", ReportMsgf: report, ProposedFn: "Empty", ProposedArgsf: "elems"},
 
 					// Bullshit, but supported by the checker:
 					// n < 0, n <= 0
@@ -84,6 +86,8 @@ func (g EmptyTestsGenerator) TemplateData() any {
 					{Fn: "NotEqualValues", Argsf: "0, len(elems)", ReportMsgf: report, ProposedFn: "NotEmpty", ProposedArgsf: "elems"},
 					{Fn: "Greater", Argsf: "len(elems), 0", ReportMsgf: report, ProposedFn: "NotEmpty", ProposedArgsf: "elems"},
 					{Fn: "Less", Argsf: "0, len(elems)", ReportMsgf: report, ProposedFn: "NotEmpty", ProposedArgsf: "elems"},
+					{Fn: "NotZero", Argsf: "len(elems)", ReportMsgf: report, ProposedFn: "NotEmpty", ProposedArgsf: "elems"},
+					{Fn: "NotEmpty", Argsf: "len(elems)", ReportMsgf: report, ProposedFn: "NotEmpty", ProposedArgsf: "elems"},
 				},
 				ValidAssertions: []Assertion{
 					{Fn: "NotEmpty", Argsf: "elems"},
@@ -161,7 +165,7 @@ func {{ .CheckerName.AsTestName }}(t *testing.T) {
 			{{- range $ai, $assrn := $test.InvalidAssertions }}
 				{{ NewAssertionExpander.Expand $assrn "assert" "t" nil }}
 			{{- end }}
-	
+
 			// Valid.
 			{{- range $ai, $assrn := $test.ValidAssertions }}
 				{{ NewAssertionExpander.Expand $assrn "assert" "t" nil }}