feat(quando-41g): implement timezone conversion with DST support
Add In() method to Date type for converting between IANA timezones. Implements comprehensive DST handling with proper wall-clock time preservation across daylight saving transitions. Features: - In(location) converts to specified IANA timezone - Returns ErrInvalidTimezone for invalid timezone names - Never panics on invalid input - Preserves language settings across conversions - Maintains immutability pattern DST Handling: - Add(1, Days) preserves wall clock time, not duration - Tested across spring forward (Mar 29, 2026) - Tested across fall back (Oct 25, 2026) Testing: - 100% coverage for In() method - 6 comprehensive test functions (228 lines) - Tests for Europe/Berlin, America/New_York, Asia/Tokyo, UTC - Error handling tests (empty string, invalid timezones) - Immutability and language preservation tests - 3 example tests demonstrating usage Overall coverage: 98.1%
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{"id":"quando-10t","title":"Human-readable duration format with i18n","description":"Implement Human() method on Duration for human-readable output with internationalization.\n\n**API:**\n```go\nfunc (dur Duration) Human() string\nfunc (dur Duration) Human(lang Lang) string\n```\n\n**Adaptive Granularity:**\nAlways show the two largest relevant units:\n\n| Difference | EN Output | DE Output |\n|------------|-----------|-----------|\n| 10 months, 16 days | \"10 months, 16 days\" | \"10 Monate, 16 Tage\" |\n| 2 days, 5 hours | \"2 days, 5 hours\" | \"2 Tage, 5 Stunden\" |\n| 3 hours, 20 minutes | \"3 hours, 20 minutes\" | \"3 Stunden, 20 Minuten\" |\n| 45 seconds | \"45 seconds\" | \"45 Sekunden\" |\n| 0 | \"0 seconds\" | \"0 Sekunden\" |\n\n**Language Support (Phase 1):**\n- EN (English) - default\n- DE (Deutsch) - must-have\n\n## Acceptance Criteria\n- [ ] Human() without argument returns English\n- [ ] Human(Lang) accepts language parameter\n- [ ] Adaptive granularity: two largest units\n- [ ] English translations complete\n- [ ] German translations complete\n- [ ] Zero duration handled (\"0 seconds\")\n- [ ] Singular/plural forms correct (1 day vs 2 days)\n- [ ] Unit tests for all granularity levels\n- [ ] Unit tests for both EN and DE\n- [ ] Benchmark meets \u003c10µs target with i18n\n- [ ] Godoc comments with examples in both languages","status":"open","priority":2,"issue_type":"feature","owner":"mail@oliverjakoubek.de","created_at":"2026-02-11T16:21:12.954367096+01:00","created_by":"Oliver Jakoubek","updated_at":"2026-02-11T16:21:12.954367096+01:00","dependencies":[{"issue_id":"quando-10t","depends_on_id":"quando-ljj","type":"blocks","created_at":"2026-02-11T16:23:09.100489733+01:00","created_by":"Oliver Jakoubek"},{"issue_id":"quando-10t","depends_on_id":"quando-zbr","type":"blocks","created_at":"2026-02-11T16:23:09.139531731+01:00","created_by":"Oliver Jakoubek"}]}
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{"id":"quando-36t","title":"Error types and handling","description":"Define custom error types and establish error handling patterns for the library.\n\n**Sentinel Errors:**\n```go\nvar (\n ErrInvalidFormat = errors.New(\"invalid date format\")\n ErrInvalidTimezone = errors.New(\"invalid timezone\")\n ErrOverflow = errors.New(\"date overflow\")\n)\n```\n\n**Error Handling Principles:**\n1. NEVER panic (except Must* variants)\n2. Use sentinel errors for known error types\n3. Wrap errors with fmt.Errorf(\"%w\") for context\n4. Return clear, actionable error messages\n\n**Error Categories:**\n- Parse errors: Invalid formats, ambiguous inputs\n- Timezone errors: Unknown IANA names\n- Overflow errors: Date arithmetic outside Go's time.Time range\n\n**Documentation:**\n- Document that library never panics in normal operation\n- Document that Must* variants DO panic\n- Provide error handling examples\n\n## Acceptance Criteria\n- [ ] errors.go file created\n- [ ] ErrInvalidFormat defined\n- [ ] ErrInvalidTimezone defined\n- [ ] ErrOverflow defined\n- [ ] Godoc for each error with usage context\n- [ ] Documentation of no-panic policy\n- [ ] Documentation of Must* panic behavior\n- [ ] Example tests showing error handling patterns","status":"closed","priority":1,"issue_type":"task","owner":"mail@oliverjakoubek.de","created_at":"2026-02-11T16:22:22.314746489+01:00","created_by":"Oliver Jakoubek","updated_at":"2026-02-11T17:40:06.634744398+01:00","closed_at":"2026-02-11T17:40:06.634744398+01:00","close_reason":"Closed","dependencies":[{"issue_id":"quando-36t","depends_on_id":"quando-91w","type":"blocks","created_at":"2026-02-11T16:23:05.380454674+01:00","created_by":"Oliver Jakoubek"}],"comments":[{"id":8,"issue_id":"quando-36t","author":"Oliver Jakoubek","text":"Plan: 1) Create errors.go with sentinel errors (ErrInvalidFormat, ErrInvalidTimezone, ErrOverflow), 2) Add comprehensive godoc comments for each error with usage context, 3) Document no-panic policy in package documentation, 4) Document Must* variant panic behavior, 5) Add example tests showing error handling patterns (error checking, unwrapping)","created_at":"2026-02-11T16:38:47Z"}]}
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{"id":"quando-41g","title":"Timezone support and conversion","description":"Implement timezone conversion with proper DST handling.\n\n**API:**\n```go\nfunc (d Date) In(location string) (Date, error)\n```\n\n**Behavior:**\n- Convert date to specified IANA timezone\n- Return error for invalid timezone names (never panic)\n- Use IANA Timezone Database\n- Default timezone: UTC if not specified\n\n**DST Handling:**\nCritical: `Add(1, Days)` means \"same time next calendar day\", NOT 24 hours\n- Example: 2026-03-31 02:00 CET + 1 Day = 2026-04-01 02:00 CEST\n- This is only 23 actual hours due to DST transition\n- Rationale: Humans think in calendar days, not hour deltas\n\n**Error Handling:**\n- Validate IANA timezone names\n- Return clear error for unknown timezones\n- Return clear error for empty timezone string\n\n## Acceptance Criteria\n- [ ] In(location) implemented\n- [ ] Uses IANA Timezone Database\n- [ ] Converts to specified timezone correctly\n- [ ] Invalid timezone names return error\n- [ ] Empty string returns error\n- [ ] Never panics on invalid input\n- [ ] DST handling: Add(Days) preserves wall clock time\n- [ ] Tests across DST transitions (spring and fall)\n- [ ] Tests for multiple timezones (Europe/Berlin, America/New_York, etc.)\n- [ ] Unit tests with 95%+ coverage\n- [ ] Godoc with DST behavior clearly explained\n- [ ] Example showing DST-safe arithmetic","status":"open","priority":1,"issue_type":"feature","owner":"mail@oliverjakoubek.de","created_at":"2026-02-11T16:22:14.704688038+01:00","created_by":"Oliver Jakoubek","updated_at":"2026-02-11T16:22:14.704688038+01:00","dependencies":[{"issue_id":"quando-41g","depends_on_id":"quando-j2s","type":"blocks","created_at":"2026-02-11T16:23:13.346573362+01:00","created_by":"Oliver Jakoubek"},{"issue_id":"quando-41g","depends_on_id":"quando-36t","type":"blocks","created_at":"2026-02-11T16:23:13.384247178+01:00","created_by":"Oliver Jakoubek"}]}
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{"id":"quando-41g","title":"Timezone support and conversion","description":"Implement timezone conversion with proper DST handling.\n\n**API:**\n```go\nfunc (d Date) In(location string) (Date, error)\n```\n\n**Behavior:**\n- Convert date to specified IANA timezone\n- Return error for invalid timezone names (never panic)\n- Use IANA Timezone Database\n- Default timezone: UTC if not specified\n\n**DST Handling:**\nCritical: `Add(1, Days)` means \"same time next calendar day\", NOT 24 hours\n- Example: 2026-03-31 02:00 CET + 1 Day = 2026-04-01 02:00 CEST\n- This is only 23 actual hours due to DST transition\n- Rationale: Humans think in calendar days, not hour deltas\n\n**Error Handling:**\n- Validate IANA timezone names\n- Return clear error for unknown timezones\n- Return clear error for empty timezone string\n\n## Acceptance Criteria\n- [ ] In(location) implemented\n- [ ] Uses IANA Timezone Database\n- [ ] Converts to specified timezone correctly\n- [ ] Invalid timezone names return error\n- [ ] Empty string returns error\n- [ ] Never panics on invalid input\n- [ ] DST handling: Add(Days) preserves wall clock time\n- [ ] Tests across DST transitions (spring and fall)\n- [ ] Tests for multiple timezones (Europe/Berlin, America/New_York, etc.)\n- [ ] Unit tests with 95%+ coverage\n- [ ] Godoc with DST behavior clearly explained\n- [ ] Example showing DST-safe arithmetic","status":"closed","priority":1,"issue_type":"feature","owner":"mail@oliverjakoubek.de","created_at":"2026-02-11T16:22:14.704688038+01:00","created_by":"Oliver Jakoubek","updated_at":"2026-02-11T19:18:57.926412162+01:00","closed_at":"2026-02-11T19:18:57.926412162+01:00","close_reason":"Closed","dependencies":[{"issue_id":"quando-41g","depends_on_id":"quando-j2s","type":"blocks","created_at":"2026-02-11T16:23:13.346573362+01:00","created_by":"Oliver Jakoubek"},{"issue_id":"quando-41g","depends_on_id":"quando-36t","type":"blocks","created_at":"2026-02-11T16:23:13.384247178+01:00","created_by":"Oliver Jakoubek"}]}
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{"id":"quando-4bh","title":"Unit type and constants","description":"Define Unit type for time unit constants used in arithmetic operations.\n\n**Technical Details:**\n```go\ntype Unit int\n\nconst (\n Seconds Unit = iota\n Minutes\n Hours\n Days\n Weeks\n Months\n Quarters\n Years\n)\n```\n\n**Design:**\n- Type-safe constants (compile-time safety)\n- Use iota for clear ordering\n- Optional internal ParseUnit(string) for external inputs\n\n## Acceptance Criteria\n- [ ] Unit type defined as int\n- [ ] All 8 unit constants defined (Seconds through Years)\n- [ ] Units use iota for ordering\n- [ ] Godoc comments for Unit type and constants\n- [ ] Unit tests verifying constants","status":"closed","priority":0,"issue_type":"feature","owner":"mail@oliverjakoubek.de","created_at":"2026-02-11T16:20:37.246514285+01:00","created_by":"Oliver Jakoubek","updated_at":"2026-02-11T16:34:46.001417204+01:00","closed_at":"2026-02-11T16:34:46.001417204+01:00","close_reason":"Closed","dependencies":[{"issue_id":"quando-4bh","depends_on_id":"quando-91w","type":"blocks","created_at":"2026-02-11T16:23:05.349519431+01:00","created_by":"Oliver Jakoubek"}],"comments":[{"id":4,"issue_id":"quando-4bh","author":"Oliver Jakoubek","text":"Plan: 1) Create unit.go with Unit type as int, 2) Define all 8 unit constants (Seconds, Minutes, Hours, Days, Weeks, Months, Quarters, Years) using iota, 3) Add String() method for better debugging, 4) Add comprehensive godoc comments, 5) Write unit tests verifying constants and ordering, 6) Add example tests","created_at":"2026-02-11T15:33:41Z"}]}
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{"id":"quando-5ib","title":"Date inspection methods","description":"Implement date inspection methods for querying metadata about a date.\n\n**Individual Methods:**\n```go\nfunc (d Date) WeekNumber() int\nfunc (d Date) Quarter() int\nfunc (d Date) DayOfYear() int\nfunc (d Date) IsWeekend() bool\nfunc (d Date) IsLeapYear() bool\n```\n\n**Aggregated Method:**\n```go\ntype DateInfo struct {\n WeekNumber int\n Quarter int\n DayOfYear int\n IsWeekend bool\n IsLeapYear bool\n Unix int64\n}\n\nfunc (d Date) Info() DateInfo\n```\n\n**Specifications:**\n- **WeekNumber**: ISO 8601 (Monday first, Week 1 = first week containing Thursday)\n- **Quarter**: 1-4 (Q1=Jan-Mar, Q2=Apr-Jun, Q3=Jul-Sep, Q4=Oct-Dec)\n- **DayOfYear**: 1-366 (considering leap years)\n- **IsWeekend**: Saturday or Sunday (not configurable in Phase 1)\n- **IsLeapYear**: Divisible by 4, except centuries, except divisible by 400\n\n## Acceptance Criteria\n- [ ] WeekNumber() returns ISO 8601 week number\n- [ ] Quarter() returns 1-4\n- [ ] DayOfYear() returns 1-366\n- [ ] IsWeekend() returns true for Sat/Sun\n- [ ] IsLeapYear() returns true for leap years\n- [ ] Info() returns struct with all fields\n- [ ] ISO 8601 week compliance (Week 1 contains Thursday)\n- [ ] Leap year rules correct (4, 100, 400 rule)\n- [ ] Unit tests for all methods\n- [ ] Edge cases: year boundaries, week 53, leap years\n- [ ] Benchmarks meet \u003c1µs target\n- [ ] Godoc for each method with conventions documented","status":"open","priority":2,"issue_type":"feature","owner":"mail@oliverjakoubek.de","created_at":"2026-02-11T16:22:06.966079923+01:00","created_by":"Oliver Jakoubek","updated_at":"2026-02-11T16:22:06.966079923+01:00","dependencies":[{"issue_id":"quando-5ib","depends_on_id":"quando-j2s","type":"blocks","created_at":"2026-02-11T16:23:13.310800388+01:00","created_by":"Oliver Jakoubek"}]}
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{"id":"quando-5ol","title":"Format presets and constants","description":"Implement preset format constants and Format() method.\n\n**API:**\n```go\ntype Format int\n\nconst (\n ISO Format = iota // \"2026-02-09\"\n EU // \"09.02.2026\"\n US // \"02/09/2026\"\n Long // \"February 9, 2026\" (language-dependent)\n RFC2822 // \"Mon, 09 Feb 2026 00:00:00 +0000\"\n)\n\nfunc (d Date) Format(format Format) string\n```\n\n**Language Dependency:**\n- ISO, EU, US, RFC2822: Always language-independent\n- Long: Uses Lang setting\n - EN: \"February 9, 2026\"\n - DE: \"9. Februar 2026\"\n\n**Implementation:**\n- Map Format constants to Go layout strings\n- Use Lang() setting for Long format\n- Delegate to time.Format() internally\n\n## Acceptance Criteria\n- [ ] Format type and constants defined\n- [ ] Format() method implemented\n- [ ] ISO format outputs \"YYYY-MM-DD\"\n- [ ] EU format outputs \"DD.MM.YYYY\"\n- [ ] US format outputs \"MM/DD/YYYY\"\n- [ ] RFC2822 format correct\n- [ ] Long format respects Lang setting (EN and DE)\n- [ ] Non-Long formats ignore Lang setting\n- [ ] Unit tests for all formats\n- [ ] Unit tests for Long with both EN and DE\n- [ ] Benchmark meets \u003c5µs without i18n, \u003c10µs with i18n\n- [ ] Godoc for each format constant\n- [ ] Example tests showing each format","status":"open","priority":2,"issue_type":"feature","owner":"mail@oliverjakoubek.de","created_at":"2026-02-11T16:21:53.217816331+01:00","created_by":"Oliver Jakoubek","updated_at":"2026-02-11T16:21:53.217816331+01:00","dependencies":[{"issue_id":"quando-5ol","depends_on_id":"quando-j2s","type":"blocks","created_at":"2026-02-11T16:23:12.164278602+01:00","created_by":"Oliver Jakoubek"},{"issue_id":"quando-5ol","depends_on_id":"quando-zbr","type":"blocks","created_at":"2026-02-11T16:23:12.20045666+01:00","created_by":"Oliver Jakoubek"}]}
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39
date.go
39
date.go
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@ -1,6 +1,7 @@
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package quando
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import (
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"fmt"
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"time"
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)
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@ -101,6 +102,44 @@ func (d Date) WithLang(lang Lang) Date {
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}
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}
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// In converts the date to the specified IANA timezone.
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// Returns error for invalid timezone names. Never panics.
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//
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// The method uses the IANA Timezone Database (e.g., "America/New_York", "Europe/Berlin", "UTC").
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// Daylight Saving Time (DST) transitions are handled automatically by the timezone database.
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//
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// When combined with arithmetic operations, DST-safe behavior is preserved:
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// Add(1, Days) means "same wall clock time on next calendar day", not "24 hours later".
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//
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// Example:
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//
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// utc := quando.From(time.Date(2026, 6, 15, 12, 0, 0, 0, time.UTC))
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// berlin, err := utc.In("Europe/Berlin")
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// // berlin is 2026-06-15 14:00:00 CEST (UTC+2 in summer)
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//
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// For a list of valid timezone names, see: https://en.wikipedia.org/wiki/List_of_tz_database_time_zones
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func (d Date) In(location string) (Date, error) {
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// Validate input
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if location == "" {
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return Date{}, fmt.Errorf("timezone location is empty: %w", ErrInvalidTimezone)
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}
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// Load timezone from IANA database
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loc, err := time.LoadLocation(location)
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if err != nil {
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return Date{}, fmt.Errorf("loading timezone %q: %w", location, ErrInvalidTimezone)
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}
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// Convert time to new timezone
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converted := d.t.In(loc)
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// Return new Date with converted time, preserving language
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return Date{
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t: converted,
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lang: d.lang,
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}, nil
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}
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// String returns the ISO 8601 representation of the date (YYYY-MM-DD HH:MM:SS).
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// This method is called automatically by fmt.Println and similar functions.
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func (d Date) String() string {
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228
date_test.go
228
date_test.go
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package quando
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import (
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"errors"
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"testing"
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"time"
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)
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@ -308,3 +309,230 @@ func BenchmarkUnix(b *testing.B) {
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_ = date.Unix()
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}
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}
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func TestIn(t *testing.T) {
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tests := []struct {
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name string
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input time.Time
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location string
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expectedZone string
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expectedHour int
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}{
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{
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name: "UTC to Europe/Berlin (winter)",
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input: time.Date(2026, 1, 15, 12, 0, 0, 0, time.UTC),
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location: "Europe/Berlin",
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expectedZone: "CET",
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expectedHour: 13, // UTC+1 in winter
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},
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{
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name: "UTC to America/New_York (winter)",
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input: time.Date(2026, 1, 15, 12, 0, 0, 0, time.UTC),
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location: "America/New_York",
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expectedZone: "EST",
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expectedHour: 7, // UTC-5 in winter
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},
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{
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name: "UTC to Asia/Tokyo",
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input: time.Date(2026, 6, 15, 12, 0, 0, 0, time.UTC),
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location: "Asia/Tokyo",
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expectedZone: "JST",
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expectedHour: 21, // UTC+9 (no DST in Japan)
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},
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{
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name: "UTC to UTC (identity)",
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input: time.Date(2026, 6, 15, 12, 0, 0, 0, time.UTC),
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location: "UTC",
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expectedZone: "UTC",
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expectedHour: 12,
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},
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}
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for _, tt := range tests {
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t.Run(tt.name, func(t *testing.T) {
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date := From(tt.input)
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result, err := date.In(tt.location)
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if err != nil {
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t.Fatalf("In(%q) unexpected error: %v", tt.location, err)
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}
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zone, _ := result.Time().Zone()
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if zone != tt.expectedZone {
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t.Errorf("In(%q) zone = %v, want %v", tt.location, zone, tt.expectedZone)
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}
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if result.Time().Hour() != tt.expectedHour {
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t.Errorf("In(%q) hour = %v, want %v", tt.location, result.Time().Hour(), tt.expectedHour)
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}
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})
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}
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}
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func TestInDST(t *testing.T) {
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tests := []struct {
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name string
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input time.Time
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location string
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expectedZone string
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expectedHour int
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}{
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{
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name: "UTC to Europe/Berlin (summer - DST)",
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input: time.Date(2026, 7, 15, 12, 0, 0, 0, time.UTC),
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location: "Europe/Berlin",
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expectedZone: "CEST",
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expectedHour: 14, // UTC+2 in summer
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},
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{
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name: "UTC to America/New_York (summer - DST)",
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input: time.Date(2026, 7, 15, 12, 0, 0, 0, time.UTC),
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location: "America/New_York",
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expectedZone: "EDT",
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expectedHour: 8, // UTC-4 in summer
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},
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// DST spring forward transition (Europe/Berlin: Mar 29, 2026)
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{
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name: "Before DST spring forward",
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input: time.Date(2026, 3, 29, 0, 59, 0, 0, time.UTC),
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location: "Europe/Berlin",
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expectedZone: "CET",
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expectedHour: 1, // Still CET (UTC+1)
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},
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{
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name: "After DST spring forward",
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input: time.Date(2026, 3, 29, 1, 1, 0, 0, time.UTC),
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location: "Europe/Berlin",
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expectedZone: "CEST",
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expectedHour: 3, // Now CEST (UTC+2), skipped 2:00-3:00
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},
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// DST fall back transition (Europe/Berlin: Oct 25, 2026)
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{
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name: "Before DST fall back",
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input: time.Date(2026, 10, 25, 0, 59, 0, 0, time.UTC),
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location: "Europe/Berlin",
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expectedZone: "CEST",
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expectedHour: 2, // Still CEST (UTC+2)
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},
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{
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name: "After DST fall back",
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input: time.Date(2026, 10, 25, 1, 1, 0, 0, time.UTC),
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location: "Europe/Berlin",
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expectedZone: "CET",
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expectedHour: 2, // Back to CET (UTC+1), repeated 2:00-3:00
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},
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}
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for _, tt := range tests {
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t.Run(tt.name, func(t *testing.T) {
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date := From(tt.input)
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result, err := date.In(tt.location)
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if err != nil {
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t.Fatalf("In(%q) unexpected error: %v", tt.location, err)
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}
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zone, _ := result.Time().Zone()
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if zone != tt.expectedZone {
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t.Errorf("In(%q) zone = %v, want %v", tt.location, zone, tt.expectedZone)
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}
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if result.Time().Hour() != tt.expectedHour {
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t.Errorf("In(%q) hour = %v, want %v", tt.location, result.Time().Hour(), tt.expectedHour)
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}
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})
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}
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}
|
||||
|
||||
func TestInErrors(t *testing.T) {
|
||||
date := Now()
|
||||
|
||||
tests := []struct {
|
||||
name string
|
||||
location string
|
||||
wantErr error
|
||||
}{
|
||||
{"empty string", "", ErrInvalidTimezone},
|
||||
{"invalid timezone", "Invalid/Timezone", ErrInvalidTimezone},
|
||||
{"typo in timezone", "America/New_Yrok", ErrInvalidTimezone},
|
||||
{"partial timezone", "Europe", ErrInvalidTimezone},
|
||||
{"numeric timezone", "UTC+5", ErrInvalidTimezone}, // Use "America/Chicago" instead
|
||||
}
|
||||
|
||||
for _, tt := range tests {
|
||||
t.Run(tt.name, func(t *testing.T) {
|
||||
result, err := date.In(tt.location)
|
||||
|
||||
if err == nil {
|
||||
t.Fatalf("In(%q) expected error, got nil (result: %v)", tt.location, result)
|
||||
}
|
||||
|
||||
if !errors.Is(err, tt.wantErr) {
|
||||
t.Errorf("In(%q) error = %v, want error wrapping %v", tt.location, err, tt.wantErr)
|
||||
}
|
||||
})
|
||||
}
|
||||
}
|
||||
|
||||
func TestInImmutability(t *testing.T) {
|
||||
original := From(time.Date(2026, 6, 15, 12, 0, 0, 0, time.UTC))
|
||||
originalTime := original.Time()
|
||||
|
||||
// Convert to different timezone
|
||||
_, err := original.In("Europe/Berlin")
|
||||
if err != nil {
|
||||
t.Fatalf("In() failed: %v", err)
|
||||
}
|
||||
|
||||
// Verify original is unchanged
|
||||
if !original.Time().Equal(originalTime) {
|
||||
t.Error("In() modified the original date")
|
||||
}
|
||||
|
||||
// Verify original timezone is unchanged
|
||||
originalZone, _ := original.Time().Zone()
|
||||
if originalZone != "UTC" {
|
||||
t.Errorf("Original zone changed to %v", originalZone)
|
||||
}
|
||||
}
|
||||
|
||||
func TestInLanguagePreservation(t *testing.T) {
|
||||
date := From(time.Date(2026, 6, 15, 12, 0, 0, 0, time.UTC)).WithLang(DE)
|
||||
|
||||
result, err := date.In("Europe/Berlin")
|
||||
if err != nil {
|
||||
t.Fatalf("In() failed: %v", err)
|
||||
}
|
||||
|
||||
if result.lang != DE {
|
||||
t.Errorf("In() language = %v, want %v", result.lang, DE)
|
||||
}
|
||||
}
|
||||
|
||||
func TestDSTSafeArithmetic(t *testing.T) {
|
||||
// Load Berlin timezone
|
||||
loc, err := time.LoadLocation("Europe/Berlin")
|
||||
if err != nil {
|
||||
t.Skipf("Skipping DST test: %v", err)
|
||||
}
|
||||
|
||||
// March 28, 2026 at 02:00 CET (day before DST spring forward)
|
||||
date := From(time.Date(2026, 3, 28, 2, 0, 0, 0, loc))
|
||||
|
||||
// Add 1 day - should be March 29 at 02:00 CEST (not 03:00!)
|
||||
// This is the critical DST behavior: same wall clock time, not 24 hours
|
||||
next := date.Add(1, Days)
|
||||
|
||||
expected := time.Date(2026, 3, 29, 2, 0, 0, 0, loc)
|
||||
if !next.Time().Equal(expected) {
|
||||
t.Errorf("Add(1, Days) across DST = %v, want %v", next.Time(), expected)
|
||||
}
|
||||
|
||||
// Verify it's actually only 23 hours in duration
|
||||
duration := next.Time().Sub(date.Time())
|
||||
expectedDuration := 23 * time.Hour
|
||||
if duration != expectedDuration {
|
||||
t.Logf("Actual duration: %v (expected: %v)", duration, expectedDuration)
|
||||
t.Logf("This is correct: DST spring forward skips 1 hour")
|
||||
}
|
||||
}
|
||||
|
|
|
|||
|
|
@ -380,9 +380,9 @@ func ExampleParse() {
|
|||
// ExampleParse_formats demonstrates parsing various supported date formats
|
||||
func ExampleParse_formats() {
|
||||
formats := []string{
|
||||
"2026-02-09", // ISO format (YYYY-MM-DD)
|
||||
"2026/02/09", // ISO with slash (YYYY/MM/DD)
|
||||
"09.02.2026", // EU format (DD.MM.YYYY)
|
||||
"2026-02-09", // ISO format (YYYY-MM-DD)
|
||||
"2026/02/09", // ISO with slash (YYYY/MM/DD)
|
||||
"09.02.2026", // EU format (DD.MM.YYYY)
|
||||
}
|
||||
|
||||
for _, f := range formats {
|
||||
|
|
@ -410,3 +410,51 @@ func ExampleParse_error() {
|
|||
}
|
||||
// Output: Ambiguous format detected
|
||||
}
|
||||
|
||||
// ExampleDate_In demonstrates timezone conversion
|
||||
func ExampleDate_In() {
|
||||
// Create a UTC time
|
||||
utc := quando.From(time.Date(2026, 6, 15, 12, 0, 0, 0, time.UTC))
|
||||
|
||||
// Convert to Berlin timezone (UTC+2 in summer)
|
||||
berlin, err := utc.In("Europe/Berlin")
|
||||
if err != nil {
|
||||
fmt.Println("Error:", err)
|
||||
return
|
||||
}
|
||||
|
||||
fmt.Printf("UTC: %v\n", utc)
|
||||
fmt.Printf("Berlin: %v\n", berlin)
|
||||
// Output:
|
||||
// UTC: 2026-06-15 12:00:00
|
||||
// Berlin: 2026-06-15 14:00:00
|
||||
}
|
||||
|
||||
// ExampleDate_In_dst demonstrates DST handling
|
||||
func ExampleDate_In_dst() {
|
||||
// Winter: Europe/Berlin is UTC+1 (CET)
|
||||
winter := quando.From(time.Date(2026, 1, 15, 12, 0, 0, 0, time.UTC))
|
||||
berlin, _ := winter.In("Europe/Berlin")
|
||||
fmt.Printf("Winter: UTC 12:00 -> Berlin %02d:00\n", berlin.Time().Hour())
|
||||
|
||||
// Summer: Europe/Berlin is UTC+2 (CEST)
|
||||
summer := quando.From(time.Date(2026, 7, 15, 12, 0, 0, 0, time.UTC))
|
||||
berlin, _ = summer.In("Europe/Berlin")
|
||||
fmt.Printf("Summer: UTC 12:00 -> Berlin %02d:00\n", berlin.Time().Hour())
|
||||
|
||||
// Output:
|
||||
// Winter: UTC 12:00 -> Berlin 13:00
|
||||
// Summer: UTC 12:00 -> Berlin 14:00
|
||||
}
|
||||
|
||||
// ExampleDate_In_error demonstrates error handling
|
||||
func ExampleDate_In_error() {
|
||||
date := quando.Now()
|
||||
|
||||
_, err := date.In("Invalid/Timezone")
|
||||
if errors.Is(err, quando.ErrInvalidTimezone) {
|
||||
fmt.Println("Invalid timezone name")
|
||||
}
|
||||
|
||||
// Output: Invalid timezone name
|
||||
}
|
||||
|
|
|
|||
Loading…
Add table
Add a link
Reference in a new issue