Merge pull request #1546 from fsprojects/daily-test-improver/csv-core-coverage

Daily Test Coverage Improver: Comprehensive CSV Core coverage improvements

Author: dsyme

tests/FSharp.Data.Core.Tests/CsvReader.fs

@@ -114,4 +114,248 @@ GHI;3
        [| "QUOTED"; "4" |]
        [| ""; "5" |] |]
 
-  actual |> should equal expected
+  actual |> should equal expected
+
+// --------------------------------------------------------------------------------------
+// Tests for CSV Core components that need better coverage
+// --------------------------------------------------------------------------------------
+
+open FSharp.Data
+
+// CsvFile tests
+[<Test>]
+let ``CsvFile.Parse can parse simple CSV`` () =
+  let csv = CsvFile.Parse("name,age\nAlice,25\nBob,30")
+  csv.Headers |> should equal (Some [| "name"; "age" |])
+  csv.Rows |> Seq.length |> should equal 2
+  let firstRow = csv.Rows |> Seq.head
+  firstRow.["name"] |> should equal "Alice"
+  firstRow.["age"] |> should equal "25"
+
+[<Test>]
+let ``CsvFile.Parse with custom separators`` () =
+  let csv = CsvFile.Parse("name;age\nAlice;25\nBob;30", separators=";")
+  csv.Headers |> should equal (Some [| "name"; "age" |])
+  let firstRow = csv.Rows |> Seq.head
+  firstRow.["name"] |> should equal "Alice"
+
+[<Test>]
+let ``CsvFile.Parse with custom quote character`` () =
+  let csv = CsvFile.Parse("name,value\nAlice,'Hello, World'", quote=''')
+  let firstRow = csv.Rows |> Seq.head
+  firstRow.["value"] |> should equal "Hello, World"
+
+[<Test>]
+let ``CsvFile.Parse without headers`` () =
+  let csv = CsvFile.Parse("Alice,25\nBob,30", hasHeaders=false)
+  csv.Headers |> should equal None
+  let firstRow = csv.Rows |> Seq.head
+  firstRow.[0] |> should equal "Alice"
+  firstRow.[1] |> should equal "25"
+
+[<Test>]
+let ``CsvFile.Parse with skipRows`` () =
+  let csv = CsvFile.Parse("comment line\nname,age\nAlice,25", skipRows=1)
+  csv.Headers |> should equal (Some [| "name"; "age" |])
+  let firstRow = csv.Rows |> Seq.head
+  firstRow.["name"] |> should equal "Alice"
+
+[<Test>]
+let ``CsvFile.Parse with ignoreErrors true handles malformed rows`` () =
+  let csv = CsvFile.Parse("name,age\nAlice,25\nBob\nCharlie,35", ignoreErrors=true)
+  csv.Rows |> Seq.length |> should equal 2 // Malformed "Bob" row should be ignored
+
+[<Test>]
+let ``CsvFile column indexing works correctly`` () =
+  let csv = CsvFile.Parse("first,second,third\nA,B,C")
+  let firstRow = csv.Rows |> Seq.head
+  firstRow.["first"] |> should equal "A"
+  firstRow.["second"] |> should equal "B"
+  firstRow.["third"] |> should equal "C"
+
+[<Test>]
+let ``CsvFile GetColumnIndex returns correct index`` () =
+  let csv = CsvFile.Parse("first,second,third\nA,B,C")
+  csv.GetColumnIndex("first") |> should equal 0
+  csv.GetColumnIndex("second") |> should equal 1
+  csv.GetColumnIndex("third") |> should equal 2
+
+[<Test>]
+let ``CsvFile TryGetColumnIndex returns Some for valid column`` () =
+  let csv = CsvFile.Parse("first,second\nA,B")
+  csv.TryGetColumnIndex("first") |> should equal (Some 0)
+  csv.TryGetColumnIndex("missing") |> should equal None
+
+[<Test>]
+let ``CsvFile GetColumnIndex throws for invalid column`` () =
+  let csv = CsvFile.Parse("first,second\nA,B")
+  (fun () -> csv.GetColumnIndex("missing") |> ignore) |> should throw typeof<System.Collections.Generic.KeyNotFoundException>
+
+// CsvExtensions edge case tests
+[<Test>]
+let ``AsInteger throws for invalid string`` () =
+  (fun () -> "not_a_number".AsInteger() |> ignore) |> should throw typeof<System.Exception>
+
+[<Test>]
+let ``AsInteger64 throws for invalid string`` () =
+  (fun () -> "not_a_number".AsInteger64() |> ignore) |> should throw typeof<System.Exception>
+
+[<Test>]
+let ``AsDecimal throws for invalid string`` () =
+  (fun () -> "not_a_decimal".AsDecimal() |> ignore) |> should throw typeof<System.Exception>
+
+[<Test>]
+let ``AsFloat throws for invalid string`` () =
+  (fun () -> "not_a_float".AsFloat() |> ignore) |> should throw typeof<System.Exception>
+
+[<Test>]
+let ``AsBoolean throws for invalid string`` () =
+  (fun () -> "not_a_bool".AsBoolean() |> ignore) |> should throw typeof<System.Exception>
+
+[<Test>]
+let ``AsDateTime throws for invalid string`` () =
+  (fun () -> "not_a_date".AsDateTime() |> ignore) |> should throw typeof<System.Exception>
+
+[<Test>]
+let ``AsGuid throws for invalid string`` () =
+  (fun () -> "not_a_guid".AsGuid() |> ignore) |> should throw typeof<System.Exception>
+
+[<Test>]
+let ``AsInteger with custom culture`` () =
+  let result = "1234".AsInteger(System.Globalization.CultureInfo.InvariantCulture)
+  result |> should equal 1234
+
+[<Test>]
+let ``AsDecimal with custom culture`` () =
+  let result = "123.45".AsDecimal(System.Globalization.CultureInfo.InvariantCulture)
+  result |> should equal 123.45m
+
+[<Test>]
+let ``AsFloat with custom culture`` () =
+  let result = "123.45".AsFloat(System.Globalization.CultureInfo.InvariantCulture)
+  result |> should equal 123.45
+
+// Additional CSV parsing edge cases
+[<Test>]
+let ``readCsvFile handles empty fields correctly`` () = 
+  let sr = new StringReader("a,,c\n,b,")
+  let actual = readCsvFile sr "," '"' |> Seq.map fst |> Array.ofSeq
+  let expected = [|[|"a"; ""; "c"|]; [|""; "b"; ""|]|]
+  actual |> should equal expected
+
+[<Test>]
+let ``readCsvFile handles trailing comma`` () = 
+  let sr = new StringReader("a,b,\nc,d,")
+  let actual = readCsvFile sr "," '"' |> Seq.map fst |> Array.ofSeq
+  let expected = [|[|"a"; "b"; ""|]; [|"c"; "d"; ""|]|]
+  actual |> should equal expected
+
+[<Test>]
+let ``readCsvFile handles quoted empty string`` () = 
+  let sr = new StringReader("a,\"\",c")
+  let actual = readCsvFile sr "," '"' |> Seq.map fst |> Array.ofSeq
+  let expected = [|[|"a"; ""; "c"|]|]
+  actual |> should equal expected
+
+[<Test>]
+let ``readCsvFile handles quotes at field boundaries`` () = 
+  let sr = new StringReader("\"a\",\"b\",\"c\"")
+  let actual = readCsvFile sr "," '"' |> Seq.map fst |> Array.ofSeq
+  let expected = [|[|"a"; "b"; "c"|]|]
+  actual |> should equal expected
+
+[<Test>]
+let ``readCsvFile handles mixed quoted and unquoted fields`` () = 
+  let sr = new StringReader("a,\"b,c\",d")
+  let actual = readCsvFile sr "," '"' |> Seq.map fst |> Array.ofSeq
+  let expected = [|[|"a"; "b,c"; "d"|]|]
+  actual |> should equal expected
+
+[<Test>]
+let ``readCsvFile handles Windows line endings`` () = 
+  let sr = new StringReader("a,b\r\nc,d\r\n")
+  let actual = readCsvFile sr "," '"' |> Seq.map fst |> Array.ofSeq
+  let expected = [|[|"a"; "b"|]; [|"c"; "d"|]|]
+  actual |> should equal expected
+
+[<Test>]
+let ``readCsvFile handles Unix line endings`` () = 
+  let sr = new StringReader("a,b\nc,d\n")
+  let actual = readCsvFile sr "," '"' |> Seq.map fst |> Array.ofSeq
+  let expected = [|[|"a"; "b"|]; [|"c"; "d"|]|]
+  actual |> should equal expected
+
+[<Test>]
+let ``readCsvFile handles Mac line endings`` () = 
+  let sr = new StringReader("a,b\rc,d\r")
+  let actual = readCsvFile sr "," '"' |> Seq.map fst |> Array.ofSeq
+  let expected = [|[|"a"; "b"|]; [|"c"; "d"|]|]
+  actual |> should equal expected
+
+[<Test>]
+let ``readCsvFile handles tab separators`` () = 
+  let sr = new StringReader("a\tb\tc\nd\te\tf")
+  let actual = readCsvFile sr "\t" '"' |> Seq.map fst |> Array.ofSeq
+  let expected = [|[|"a"; "b"; "c"|]; [|"d"; "e"; "f"|]|]
+  actual |> should equal expected
+
+[<Test>]
+let ``readCsvFile handles pipe separators`` () = 
+  let sr = new StringReader("a|b|c\nd|e|f")
+  let actual = readCsvFile sr "|" '"' |> Seq.map fst |> Array.ofSeq
+  let expected = [|[|"a"; "b"; "c"|]; [|"d"; "e"; "f"|]|]
+  actual |> should equal expected
+
+[<Test>]
+let ``readCsvFile handles single field`` () = 
+  let sr = new StringReader("single")
+  let actual = readCsvFile sr "," '"' |> Seq.map fst |> Array.ofSeq
+  let expected = [|[|"single"|]|]
+  actual |> should equal expected
+
+[<Test>]
+let ``readCsvFile handles quoted field with internal quotes`` () = 
+  let sr = new StringReader("\"She said \"\"Hello\"\" to me\"")
+  let actual = readCsvFile sr "," '"' |> Seq.map fst |> Array.ofSeq
+  let expected = [|[|"She said \"Hello\" to me"|]|]
+  actual |> should equal expected
+
+[<Test>]
+let ``readCsvFile handles BOM in stream`` () = 
+  // BOM (Byte Order Mark) should be handled gracefully
+  let bomString = "\uFEFFa,b,c"
+  let sr = new StringReader(bomString)
+  let actual = readCsvFile sr "," '"' |> Seq.map fst |> Array.ofSeq
+  // Should handle BOM by treating it as part of first field
+  actual.Length |> should be (greaterThan 0)
+
+[<Test>]
+let ``CsvFile Parse handles various numeric formats`` () =
+  let csv = CsvFile.Parse("int,float,decimal\n42,3.14,123.456")
+  let row = csv.Rows |> Seq.head
+  row.["int"] |> should equal "42"
+  row.["float"] |> should equal "3.14" 
+  row.["decimal"] |> should equal "123.456"
+
+[<Test>]
+let ``CsvFile with different column counts when ignoreErrors is false`` () =
+  (fun () -> 
+    let csv = CsvFile.Parse("a,b\n1,2,3", ignoreErrors=false)
+    csv.Rows |> Seq.toArray |> ignore
+  ) |> should throw typeof<System.Exception>
+
+[<Test>]
+let ``CsvRow GetColumn by index works correctly`` () =
+  let csv = CsvFile.Parse("a,b,c\n1,2,3")
+  let row = csv.Rows |> Seq.head
+  row.GetColumn(0) |> should equal "1"
+  row.GetColumn(1) |> should equal "2"
+  row.GetColumn(2) |> should equal "3"
+
+[<Test>]
+let ``CsvRow GetColumn by name works correctly`` () =
+  let csv = CsvFile.Parse("first,second,third\nx,y,z")
+  let row = csv.Rows |> Seq.head
+  row.GetColumn("first") |> should equal "x"
+  row.GetColumn("second") |> should equal "y" 
+  row.GetColumn("third") |> should equal "z"