# UAT: Time Travel Query (as_of Snapshot)

**Date:** YYYY-MM-DD
**Feature:** Historical Snapshot Queries
**Status:** [ ] PASS / [ ] FAIL / [ ] BLOCKED

## Scenario

Query the knowledge graph as it existed at a specific point in time. This enables:
- Audit trails ("What did we know on date X?")
- Debugging ("Why did the agent make that decision?")
- Historical analysis

## Acceptance Criteria

| Criterion | Expected | Met? |
|-----------|----------|------|
| Current query | Returns all assertions | [ ] |
| `as_of` past date | Returns only assertions before date | [ ] |
| `as_of` before data | Returns empty | [ ] |
| Newer data excluded | Verified | [ ] |
| Epoch-aware + as_of | Both filters applied | [ ] |

## Test Matrix

| Step | Action | Expected | Actual | Status |
|------|--------|----------|--------|--------|
| 1 | Create assertion at T1 | Hash returned | | [ ] |
| 2 | Create assertion at T2 | Hash returned | | [ ] |
| 3 | Create assertion at T3 | Hash returned | | [ ] |
| 4 | Query as_of=T1 | Only T1 assertion | | [ ] |
| 5 | Query as_of=T2 | T1 and T2 assertions | | [ ] |
| 6 | Query as_of=T0 (before) | Empty | | [ ] |
| 7 | Query current | All 3 assertions | | [ ] |

## Setup Commands

```bash
# Start StemeDB
cargo run --bin stemedb-api &
sleep 2
```

## Test Commands

### Record Timestamps

```bash
# Record T0 (before any data)
T0=$(date +%s)
sleep 1
```

### Step 1: Create Assertion at T1

```bash
T1=$(date +%s)

curl -X POST http://localhost:18180/v1/assertions \
  -H "Content-Type: application/json" \
  -d '{
    "subject": "Semaglutide",
    "predicate": "max_approved_dose_mg",
    "object": {"Number": 1.0},
    "confidence": 1.0,
    "source_class": "Regulatory"
  }'

echo "T1 = $T1"
sleep 2
```

**Expected:** Hash returned
**Actual:**
**Status:** [ ]

### Step 2: Create Assertion at T2 (Dose Increase)

```bash
T2=$(date +%s)

curl -X POST http://localhost:18180/v1/assertions \
  -H "Content-Type: application/json" \
  -d '{
    "subject": "Semaglutide",
    "predicate": "max_approved_dose_mg",
    "object": {"Number": 2.4},
    "confidence": 1.0,
    "source_class": "Regulatory"
  }'

echo "T2 = $T2"
sleep 2
```

**Expected:** Hash returned
**Actual:**
**Status:** [ ]

### Step 3: Create Assertion at T3 (Formulation Variant)

```bash
T3=$(date +%s)

curl -X POST http://localhost:18180/v1/assertions \
  -H "Content-Type: application/json" \
  -d '{
    "subject": "Semaglutide:Oral",
    "predicate": "max_approved_dose_mg",
    "object": {"Number": 14.0},
    "confidence": 1.0,
    "source_class": "Regulatory"
  }'

echo "T3 = $T3"
```

**Expected:** Hash returned
**Actual:**
**Status:** [ ]

### Step 4: Query as_of=T1 (Historical Snapshot)

```bash
# Should only see the 1.0mg dose
curl "http://localhost:18180/v1/query?subject=Semaglutide&predicate=max_approved_dose_mg&as_of=$T1"
```

**Expected:** Returns only `{"Number": 1.0}` assertion
**Actual:**
**Status:** [ ]

### Step 5: Query as_of=T2

```bash
# Should see 1.0mg and 2.4mg doses
curl "http://localhost:18180/v1/query?subject=Semaglutide&predicate=max_approved_dose_mg&as_of=$T2"
```

**Expected:** Returns both 1.0 and 2.4 assertions
**Actual:**
**Status:** [ ]

### Step 6: Query as_of=T0 (Before Any Data)

```bash
curl "http://localhost:18180/v1/query?subject=Semaglutide&predicate=max_approved_dose_mg&as_of=$T0"
```

**Expected:** Empty result (no assertions existed yet)
**Actual:**
**Status:** [ ]

### Step 7: Query Current (No as_of)

```bash
curl "http://localhost:18180/v1/query?subject=Semaglutide&predicate=max_approved_dose_mg"
```

**Expected:** Returns all 3 assertions (including Oral formulation)
**Actual:**
**Status:** [ ]

## Edge Cases

### ISO 8601 Date Format

```bash
# Using ISO format instead of Unix timestamp
curl "http://localhost:18180/v1/query?subject=Semaglutide&as_of=2023-06-15T00:00:00Z"
```

**Expected:** Works with ISO 8601 format
**Actual:**
**Status:** [ ]

### as_of + lens Combination

```bash
# Time travel + recency lens
curl "http://localhost:18180/v1/query?subject=Semaglutide&predicate=max_approved_dose_mg&as_of=$T2&lens=recency"
```

**Expected:** Returns most recent (by T2 standards) which is 2.4mg
**Actual:**
**Status:** [ ]

## Sign-Off Checklist

- [ ] Historical snapshot returns only assertions before date
- [ ] Future assertions excluded
- [ ] Empty result for dates before data
- [ ] Current query returns all
- [ ] ISO 8601 date format supported
- [ ] Combines correctly with other filters (lens, epoch)

## Notes

*Time travel queries are read-only views. The underlying assertions are immutable and not affected by as_of filters.*

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**Tester:**
**Date:**
**Result:**