GH-38751: [C++][Go][Parquet] Add tests for reading Float16 files in p…

…arquet-testing (#38753)

### Rationale for this change

Validates compatibility between implementations when reading `Float16` columns.

### What changes are included in this PR?

- Bumps `parquet-testing` commit to latest to use the recently-added files
- Adds reader tests for C++ and Go in the same vein as apache/arrow-rs#5003

### Are these changes tested?

Yes

### Are there any user-facing changes?

No

* Closes: #38751

Authored-by: benibus <[email protected]>
Signed-off-by: Matt Topol <[email protected]>

parquet/pqarrow/file_reader_test.go

@@ -29,6 +29,7 @@ import (
 	"github.com/apache/arrow/go/v15/arrow"
 	"github.com/apache/arrow/go/v15/arrow/array"
 	"github.com/apache/arrow/go/v15/arrow/decimal128"
+	"github.com/apache/arrow/go/v15/arrow/float16"
 	"github.com/apache/arrow/go/v15/arrow/memory"
 	"github.com/apache/arrow/go/v15/parquet"
 	"github.com/apache/arrow/go/v15/parquet/file"
@@ -100,6 +101,72 @@ func TestArrowReaderAdHocReadDecimals(t *testing.T) {
 	}
 }
 
+func TestArrowReaderAdHocReadFloat16s(t *testing.T) {
+	tests := []struct {
+		file string
+		len  int
+		vals []float16.Num
+	}{
+		{"float16_nonzeros_and_nans", 8,
+			[]float16.Num{
+				float16.New(1.0),
+				float16.New(-2.0),
+				float16.NaN(),
+				float16.New(0.0),
+				float16.New(-1.0),
+				float16.New(0.0).Negate(),
+				float16.New(2.0),
+			}},
+		{"float16_zeros_and_nans", 3,
+			[]float16.Num{
+				float16.New(0.0),
+				float16.NaN(),
+			}},
+	}
+
+	dataDir := getDataDir()
+	for _, tt := range tests {
+		t.Run(tt.file, func(t *testing.T) {
+			mem := memory.NewCheckedAllocator(memory.DefaultAllocator)
+			defer mem.AssertSize(t, 0)
+
+			filename := filepath.Join(dataDir, tt.file+".parquet")
+			require.FileExists(t, filename)
+
+			rdr, err := file.OpenParquetFile(filename, false, file.WithReadProps(parquet.NewReaderProperties(mem)))
+			require.NoError(t, err)
+			defer rdr.Close()
+
+			arrowRdr, err := pqarrow.NewFileReader(rdr, pqarrow.ArrowReadProperties{}, mem)
+			require.NoError(t, err)
+
+			tbl, err := arrowRdr.ReadTable(context.Background())
+			require.NoError(t, err)
+			defer tbl.Release()
+
+			assert.EqualValues(t, 1, tbl.NumCols())
+			assert.Truef(t, arrow.TypeEqual(tbl.Schema().Field(0).Type, &arrow.Float16Type{}), "expected: %s\ngot: %s", tbl.Schema().Field(0).Type, arrow.Float16Type{})
+
+			valCol := tbl.Column(0)
+			assert.EqualValues(t, tt.len, valCol.Len())
+			assert.Len(t, valCol.Data().Chunks(), 1)
+
+			chunk := valCol.Data().Chunk(0).(*array.Float16)
+			assert.True(t, chunk.IsNull(0))
+			for i := 0; i < tt.len-1; i++ {
+				expected := tt.vals[i]
+				actual := chunk.Value(i + 1)
+				if expected.IsNaN() {
+					// NaN representations aren't guaranteed to be exact on a binary level
+					assert.True(t, actual.IsNaN())
+				} else {
+					assert.Equal(t, expected.Uint16(), actual.Uint16())
+				}
+			}
+		})
+	}
+}
+
 func TestRecordReaderParallel(t *testing.T) {
 	mem := memory.NewCheckedAllocator(memory.DefaultAllocator)
 	defer mem.AssertSize(t, 0)